Jesús Capistrán

Calibración de Fotodiodos OPT101

2021-10-15T17:53:00.006-05:00

Antes de comenzar a trabajar en depósito químico hace dos semanas estuve trabajando en la calibración de fotodiodos para poder colocar un piranómetro de bajo costo en base de los opt101.

Lo último que realicé fue la calibración, y un prototipo en PVC del cuerpo del instrumento.

Aquí les presento los datos recolectados para la calibración

Se puede observar que la correlación que más se aproxima a los datos experimentales es una curva cuadrática del tipo polinomial.

How to add math on your blog : MathJax + Blogger

2020-01-12T13:07:00.003-06:00

This tip is useful for engineering and science bloggers who want to share their knowledge on the web. Here is the way I found. I recently tested it on the blogger system, the purpose is to share science tutorials with you using the correct math way.

Let's do it!

Draft on paper of the Debye-Scherrer equation for crystal size calculation

Step 1: Add a new gadget to your blog and copy and paste the following script.

<script src="https://polyfill.io/v3/polyfill.min.js?features=es6"></script>
<script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js"></script>

Step 2: Write code in a new post following using latex language inside:

Inline \( latex code here \)
Paragraph \[ latex code here \]

Step 3: Equation test: Debye -Scherrer for crystal size calculation
\[ D(\text{nm}) = \frac{0.9 \lambda}{\beta\cos{\theta}} \]

D: Crystal size
\(\lambda\) : 0.15406 nm X-Ray wavelength
\(\beta\) : FWHM in radians (Full width at half maximum)
\(\theta\) : Angle location of the peak in radians.

If you have any questions, please comment on the post.

Samples from : https://www.mathjax.org/#samples

The Quadratic Formula

\[ x = {-b \pm \sqrt{b^2-4ac} \over 2a} \]

Cauchy's Integral Formula

\[ f(a) = \frac{1}{2\pi i} \oint\frac{f(z)}{z-a}dz \]

Angle Sum Formula for Cosines

\[ \cos(\theta+\phi)=\cos(\theta)\cos(\phi)−\sin(\theta)\sin(\phi) \]

Gauss' Divergence Theorem

\[ \int_D ({\nabla\cdot} F)dV=\int_{\partial D} F\cdot ndS \]

Curl of a Vector Field

\[ \vec{\nabla} \times \vec{F} = \left( \frac{\partial F_z}{\partial y} - \frac{\partial F_y}{\partial z} \right) \mathbf{i} + \left( \frac{\partial F_x}{\partial z} - \frac{\partial F_z}{\partial x} \right) \mathbf{j} + \left( \frac{\partial F_y}{\partial x} - \frac{\partial F_x}{\partial y} \right) \mathbf{k} \]

Standard Deviation

\[ \sigma = \sqrt{ \frac{1}{N} \sum_{i=1}^N (x_i -\mu)^2} \]

Definition of Christoffel Symbols

\[ (\nabla_X Y)^k = X^i (\nabla_i Y)^k = X^i \left( \frac{\partial Y^k}{\partial x^i} + \Gamma_{im}^k Y^m \right) \]

Exploring the XRD system at IFUAP

2020-01-08T21:30:00.001-06:00

A scientist is continuously seeking the truth of nature. There is a jungle of fields to explore from material science to the universe, a scientist could be doing experiments at the laboratory, or maybe they just need a comfortable place to think and create new theories which will explain new phenomena.

Training day: XRD System and software High Score Plus, BUAP

Today I was able to explore the XRD system at IFUAP (shown in the above picture). The purpose of this visit was to analyze a previous measured XRD pattern. Gratefully the responsible researcher allows me to manipulate the software High Score Plus to perform a qualitative analysis to identify the phases in the material.

High Score plus, performing phase analysis, and calculation of crystal size.

To identify the phase three steps should be performed in the following sequence:

Background determination: This is a must step due phase analysis depends on it.
Peak search: Automatic + Manual is the best
Phase analysis: Should be restricted to the constitutive elements to gain time. In my case, the restriction increase using just inorganic materials and star quality powder diffraction files (PDFs) from the database.

Once these three steps are done, the analysis gives you three important values:

Background: This information is necessary to make a good report where the background should be extracted from the observed XRD measurement.
Constitutive phases: This data confirms if your material is pure or is mixed
Crystal size: This parameter gives the size domain D < 100 nm makes you think in the nanoworld.

If you want to know how the XRD system works watch the following video:

Have you ever seen an XRD system with your own eyes?

Challenge: Share your ride !

2020-01-05T19:06:00.002-06:00

Downtown Puebla street - Callejon del Sapo

A month ago, I was traveling by bus from Morelos to Puebla city during the night. When I ask for my stop around 21-22 hours, more people get down too. It was a scary scene due there were just two local taxi units and no more transportation. Therefore, there was no other choice than ask for an Uber ride. I observe the situation. Almost everybody was using their cellphone to call their friends or families.

Two cars get immediately and lift three persons. Then a young boy and I kept there a little bit more. We were waiting for a better tariff of the Uber. As the price was elevated, I decided to ask him. Do you want to share the ride? When he said, I already pick one. And it will get here in a minute. Suddenly he surprises me, asking back, "If you want, I can pick you up to a safer place." I accept and think:

If you break the ice you will be able to offer or get a ride

Last weekend during midday I was standing at the bus stop an older man was there too. We wait for 10-15 minutes, and the bus did not appear. What was happening with public transportation? I did not know, but I felt it was unsafe to keep in one place for an extended period. Then I proceed to get an Uber and remember the last day when the young guy offers me a ride. This DejaVu makes me think: Its time to get back, Let's share my ride.

I know it is difficult to open a conversation with somebody you don't know, but if there is a purpose where you can help somebody else. Then there is an excellent opportunity to show gratitude. I think this challenge will promote kind gestures, like the movie Pay it Forward when somebody receives the support he must pay it forward and create a change. It is a great movie, I can give you the link if you want to watch in old ways DVD.

Pay it forward movie: https://amzn.to/2FjgkXR

This challenge its a way to give something. Have you ever share something like a ride, a book, a cup of coffee? Well, you can share your story in the comments below. Have a great day, and remember. Small things make a bigger difference.

Winter vacation of a Mexican young scientist

2020-01-01T07:27:00.002-06:00

Reading Alebrijes by Cecilia Reyes

Winter vacation on the public school system means three full weeks doing something else; personal stuff maybe, I am not sure about working but resting is a must.

As a postdoctoral fellowship, I am not able to get into the university facilities to do some office or experimental work in the laboratory. That means that all the experimental work is on a pause. Well, this situation brings me to the next question.

Is it healthy to continue working during vacations ? I mean, doing some reading or drafting a manuscript for a scientific publication.

For Ph.D. holders who are working right now on Mexican universities and who already got the National Research system grant (SNI-CONACYT) maybe it is a duty to work during vacations because of the process to obtain a product (student graduation, scientific publication, patents as innovation ) take a lot of time. For those who are not familiar with SNI systems, every three years we are evaluated and if we do not fill the minimum requirement to maintain the grant then the membership and grant are retired.

I remember that when I was a Ph.D. student from 2013-2017 at UNAM, we used to work during vacations because when there is a big resting time we usually got out of focus from the research project. In my experience, I always recommend my colleagues to not take vacations during the thesis writing process because there is a risk of losing focus or inspiration. But now is slightly different.

Taking vacations, rest and go with your family but maybe it is ok but I thin not full time. For example in my experience, I do nothing related to work during the two weeks but right now I begin to feel not productive. I react to this feeling by doing some activities called "Hobbies".

I used to do three constant activities: Reading, programming learning and right now writing.

Sometimes these activities are not related to science, for example, my reading motivation of this year is to be able to answer the following questions: What is it happening outside of my country in a political way?; How the human being got here to the actual world?. An, of course, be present about the environmental situation.

This is the last vacation week: What are you going to do? Travel, Read, Vist your friends, Go with your Family, Work or maybe learn something new.

Alebrijes - Lectura p.127-129

2019-12-16T12:00:00.001-06:00

Lectura corta, páginas 127-129. Excelente libro para disfrutar en compañía de tu ser querido, cuenta la historia del artesano cartonero Pedro Linares López inventor de los Alebrijes en México del siglo XX.

Consíguelo aquí: https://amzn.to/34YcKNN

AFM Training - Tip functions

2019-12-12T10:19:00.004-06:00

Equipmen: AFM Bruker Dimension Edge

Responsible research: Dr. Francisco Flores

Day: 2

Today I observe how a point for AFM is changed: We need to choose it depending on the material and the measurement we want to perform. For example, the sample of today is gold nanoparticles over a glass substrate then we have tried the TAP300Al-G which is a probe from the company BudgetSensors. This probe is designed for AFM in Tapping mode and is coated with reflective aluminum.

From the company BudgetSensor, we can discover the function of the tip models:

No coating: is designed for topography purpose
Backside aluminum coating: is designed to enhance the laser reflectivity and ensure stable measurement form highly reflective surfaces.
Backside Gold coating (inertness): is designed for stable reflection measurement in liquids.
Overall coated Gold: is designed and used for Biological Samples and aggressive chemical ambients. Often use for TIP functionalization.
Cr and Pt coated probe: is designed for electrical measurement like electrostatic force microscopy.
Diamond-like carbon coating: enhance the durability of the tip and is designed to perform many consecutive scans

Here are some photographies from the training day:

Figure 1: Change of Tip for AFM Measurement in Bruker Dimension Edge

Figure 2: Responsible researcher placing the tip in the AFM equipment

Figure 3: Getting the sample inside (gold nanoparticles deposited on glass substrate)

What are preprints?

2019-12-10T07:12:00.001-06:00

Preprint vs traditional paper submission. When I was pursuing my bachelor's degree I went to a research center and the first thing I read there was "Science that is not shared is not science" then I had the opportunity to enter this fascinating world of thinkers, conquers or discoverers.

But, How to share science? There are two ways one is peer review paper manuscript where you are reporting to science community your research this way time schedule is important In my experience 1 year of research is resume in a manuscript which is submitted to the Journal and there peers review can last from 1 - 8 months for a response. If this is favorable the publishing date is scheduled but if not correction suggestion should be made before.

How about pre-print? This way is new for the community, Actually, my doctoral and postdoctoral advisor are not using it. That's why I am here. Looking on the internet for ideas. We can take advantage of this new method. For sure, sharing new discoveries is the idea of science communication, but the opportunity to have feedback is amazing. Because in that way is how knowledge is built.

Feel free to watch the video. Now we need to discover where is the adequate server for preprint submission (at the same time as the peer review journal submission).

Cornel University: Arxiv.org

Condensed Matter (Solid state physics) - Link

physics.optics
cond-mat.mtrl-sci
physics.app-ph

ChemRxiv: The Preprint Server for Chemistry

AFM training: Bruker Dimension Edge at IFUAP

2019-12-09T21:08:00.001-06:00

Equipmen: AFM Bruker Dimension Edge

Responsible research: Dr. Francisco Flores

Day: 1

First training day on AFM Bruker Dimension Edge AFM at the Physics Institute of BUAP. This equipment will allow the measurement of topography properties like roughness and grain size. The researcher in charge explains too that it's possible to acquire electrical conductivity and work function from the surface of the films.

URL: Product overview

Model: AFM - Bruker Dimension Edge

Close up of AFM equipment

Connection block card: National Instrument BNC 2110

Alebrijes - Libro de Cecilia Reyes

2019-12-06T08:11:00.001-06:00

Lectura corta, páginas 47-49. Excelente libro para disfrutar en compañía de tu ser querido, cuenta la historia del artesano cartonero Pedro Linares López inventor de los Alebrijes en México del siglo XX. Consíguelo aquí: https://amzn.to/34YcKNN
-- Un homenaje a la creación del artesano mexicano Pedro Linares López quien en un trance cercano a la muerte tuvo la visión de animales tenebrosos que no eran de este mundo y que más tarde, gracias a su imaginación y a la magia de sus manos, fue capaz de traer a la realidad. "Alebrijes alebrijes", escuchó que gritaban en su sueño.

Laboratory - Bismuth Sulfide thin films

2019-12-05T00:22:00.001-06:00

Location: Physics Institute of BUAP, Puebla, Pue.

Chemical deposition: Bi2S3 Bismuth Sulfide

Supervisor: M.C Denisse Loeza

Chemical deposition of bismuth sulfide from the master thesis work of M.C. Denisse Loeza. This work has the intention to develop new materials (semiconductors) for solar cells. Like the ternary compound Cu3BiS3, which posses potential properties as a p-type semiconductor for absorber layer on thin-film technology.

Fig.1: Washing Bi2S3 thin films after chemical deposition

Fig.2: Dry using N2 gas

Fig.3: Another angle showing the base where the glass substrates are held.

Advance Materials group at IFUAP-BUAP

2019-11-17T16:31:00.003-06:00

Dra. Mou Pal group: Research and development of metal chalcogenides, metal oxides nanoparticles. ( Happy Birthday ) From left to right: Andres, Marifer, Cancino, Dra. Mou Pal, Denise, Me (Jesus Capistran).

Is it hard to get a postdoctoral stay in Mexico?

2019-11-17T16:24:00.005-06:00

Coffee cup at IFUAP-BUAP (From MIT)

In Mexico, 2019 is a hard year for Science and technology due to two main reasons: a) Change of Mexican president followed with a change of political flagship and b) Corruption priority besides economical aspects.

This year I had the opportunity to apply for a postdoctoral fellowship from Conacyt-International to spend one year at EMPA-Switzerland. In August, the results came and I was not selected. These results are followed by a reduction of federal found for Conacyt and the government bet for carbon-based fuels.

Fortunately, I had a plan B. I apply for a postdoctoral fellowship at the BUAP founded by the program SEP-PRODEP. The process for a stay from PRODEP is really slow, the application opens in February and closes the last day of September. The problem is the results they come from a minimum time of 3 months. In my case, the results came after 6 months of wait.

Last week IFUAP-BUAP give the results they accept my stay but I should move quickly to Puebla City. For that reason here I am taking a cup of coffee from the cafeteria at IFUAP. How a great surprise they give me before the winter season. I feel great in one of the best institutions and universities in Mexico for superior education or bachelor grade.

If you are a new 2019-postdoctoral working in Mexico please tell us: How was your experience getting that position? If you are interested in a postdoctoral position, please check these three opportunities:

CONACYT (Choose wisely: National or International)
SEP-PRODEP
UNAM-DGAPA

Note:

You are allowed to apply for the three in a row during the year. Do it and don't lose opportunities.

How to get Project Management skills for Scientists

2019-11-01T09:21:00.001-06:00

Photo by Nathan McBride on Unsplash

I have the opportunity to be the Solar Semiconductors Morelos (StartUp) founder partner, this young company gives me the profile of an entrepreneur looking for opportunities related to the energy sector. Last days I had the chance to reach the industry, government, and academic actors. Here, I realize there will be a push (investment) for new projects related to the acquisition of renewables on companies and government. But, How a scientist can touch this sector?

A scientist is a person who creates and solve problems using science and technology

A scientist solves problems using scientific methodology and international scientific literature. However, the question is How a scientist fits on a company with no research department? When I ask for advice from a businessman, he said that I should know what kind of job I am looking for. For example, doing a job search at Tesla Company, I found jobs for Energy Analysts. This job is located in the Operation and Business section, and the requirements can be fit for people with a bachelor's degree.

Going to the industry from a science profile means to pivot to engineering or going to an entrepreneur adventure on innovation.

If we analyze the path of a scientist who wants to become an entrepreneur doing innovation, then some skills are needed, like business and management. Here is why the need for project management certification. In this era, there is a lot of information, but it needs to be trusting information; that's why I will use and recommend EDX for online preparation. (About EDX Micromasters®)

1. EDX Platform offers a free online course (information), but the certification has a low cost. It is essential to acquire knowledge and skills, but if you have the financial support, a certification shows the company your skills. Here is a MicroMaster, ® on Project Management skills, need if you a scientist wants to become an entrepreneur.

RITx Project Management MicroMasters® Program

Project management: Life cycle
Best practices for project management success
International project management

2. PMI.ORG - Online courses. This entity is the international Project Management Institute that offers preparation courses and certification for project managers. I am not getting a course here, but I will look for the PMBOOK® Guide and Standards (English), you cand find here the Spanish version: Gúia del PMBOOK®"

The purpose here after reading this book is to acquire the project management language. Are you looking for the same skills? Let me tell you about my experience at the next meeting with the businessmen. But for now, What are you looking for? Are you an entrepreneur scientist?

Job Interview - Cluster Puebla - Artifex Angels

2019-10-30T14:44:00.000-06:00

Yesterday, I had the fortune to meet three founders of Artifex Angels at Titanium Tower. When I get to the lobby, the next message can be read on the wall.

Titanium tower provides business space solutions to medium and large firms. It offers a strategic location for international business in Mexico as well as a unique setting for entrepreneurs.

What a great message for an entrepreneur researcher (academic) because I found a place where real businesses are done, and maybe after this job interview, I could begin the path to become a business leader on innovation in the renewable energy sector.

This place makes me realize I have new dreams to catch as an entrepreneur seeking and promoting the acquisition of renewables, or as one of the founders said, you could be an articulator (linker) between industry and the hubs for new business.

What do you think was the result of the job interview?

You Should Learn to Program: Christian Genco at TEDxSMU

2019-10-23T06:57:00.001-05:00

Hub de innovación tecnológica: Eficiencia energética y Energías Renovables

2019-10-21T15:16:00.000-05:00

Step by step, we should lead the science from the university labs to the marketplace. There will be no opportunities if you don't seek them. Solar Semiconductors Morelos will attend this meeting looking for strategic partners inside the industry and technical collaboration with GIZ and the Queretaro innovators.

References:

Hobby: Lectura El Libro Salvaje (extracto)

2019-10-17T06:19:00.001-05:00

Extracto del libro salvaje , primer capítulo ( Separación) del autor Juan Villoro
Lector: Jesús Capistrán Libro en Amazon: https://amzn.to/2pwJPAw

How to read a scientific paper in just three steps

2019-10-15T17:55:00.000-05:00

Reading on paper is an old school way to annotate
and highlight the most interesting elements

For a scientist, reading is a must responsibility in the modern world of information, this task allows us to update the state of the art of the current research. For example, the objective of my work is to reproduce and improve antimony sulfo-selenide thin-film solar cells. Therefore, the first thing I did before experimental research It was to read the updated literature. As I am in touch with the author of the paper of interest I asked him about it's last published paper where their group develops Sb-S-Se photovoltaic mini-module prototypes.

P.K. Nair*, J.D.G. Sánchez, L.G. Martínez, P.Y.G. Ayala, A.K.M. Peñaloza, A.B. León, Y.C. García, J. Campos Álvarez, M.T.S. Nair, Chemically Deposited Antimony Sulfide Selenide Thin Film Photovoltaic Prototype Modules, ECS J. Solid State Sci. Technol. 8 (2019) Q89–Q95. doi:10.1149/2.0101906jss.

To fully understand, I almost read a scientific paper three times:

First: Print it or read it on PDF (Mendeley could help), the important thing here is to read from the beginning to the end as soon as possible.
Second: Make annotations for later discussion and highlights from the most important elements you can find on the text.
Third: Write a resume, this will allow you to save the essential information in the same notebook of literature review. I prefer to write it on the Blogspot or a note on the Evernote app following the next template.

Read more, to discover the structure or template for paper review, here you are going to write just the notes and highlighted parts. This is my way to learn fast. If you have an alternate strategy please feel free to share it in the comments section.

Paper: Chemically deposited antimony sulfide selenide thin film photovoltaic prototype modules

2019-10-14T21:12:00.001-05:00

Authors: P. K. Nair, José Diego Gonzaga Sánchez, Laura Guerrero Martínez, Perla Yoloxóchitl García Ayala, Ana Karen Martínez Peñaloza, Alessandra Beauregard León, Yareli Colín García, José Campos Álvarez, and M. T. S. Nair

Link: ECS Journal of Solid State Science and Technology, 8 (6) Q89-Q95 (2019)

Abstract

We present thin film antimony sulfide selenide prototype photovoltaic modules of area, seven cm2 and conversion efficiency (η) of 3.5%. The thin films of Sb2SxSe3-x (x, 0.8–1.6) of 120–180 nm in thickness were deposited on FTO/CdS(80 nm) substrates at 80°C from chemical bath containing potassium antimony tartrate, thioacetamide and sodium selenosulfate. Thin film of CdS of 80 nm in thickness was deposited from a chemical bath at 80°C during 65 min on fluorine-doped SnO2 (FTO). The solar cell structure FTO/CdS/Sb2SxSe3-x/C had colloidal graphite paint of area, 0.7 cm× 0.7 cm. This cell structure was heated at 300°C during 30 min in a nitrogen ambient to create a carbon-doped antimony chalcogenide layer. Silver paint was applied to the carbon electrode and on FTO around it. Prototype modules had seven series connected cells of one cm2 each with a total area of seven cm2. Solar cell with varying composition of Sb2SxSe3-x along its thickness had a η of 3.88% at an open circuit voltage (Voc) of 0.44 V and short circuit current density of 18.3 mA/cm2. Prototype modules lighted-up blue light emitting diodes at a power, 5–15 mW.

Highlights

The best solar cell is: Voc = 441 mV, Jsc = 18.34 mA/cm2, FF = 0.48 and efficiency = 3.88 % measured under standar conditions of 1 sun (Solar simulator).
Application of carbon paint over chalcogenide layer and subsequent heating of the entire cell structure would create a carbon-doped antimony chalcogenide layer

Device fabrication

Substrate: TEC7
Window layer: CdS by chemical deposition (80 nm)
Absorber layer: Sb-S-Se by sequential chemical deposition (180 nm)
Back contact: Graphite paint (SPI) / Silver paint (N2 heat treatment, 300 ºC)

Characterization techniques

EDS - Over finished solar cells
GIXRD - Over solar cell
T and R - Optical for calculation of absorption coefficient, bandgap and photogenerated current (JL)
JC curve for solar cell and mini-modules
EQE for solar cells

Notes:

This work is open for improvements in all the constitutive components of the solar cell device.

Fabrication of Titanium dioxide as a compact layer for Perovskite and thin-film solar cells

2019-10-03T05:06:00.000-05:00

Special thanks for Dra Hailin Zao Hu at IER-UNAM who let me collaborate and learn from their group the methodology for TiO2 compact layer deposition. All the training was possible with the assistance of Ph.D. student Fabian and undergraduate Ing. Gabriela Abrego from UTEZ.

Preparing TCO with magic tape for HRT layer deposition

Spin coater and micropipette are the essential tools for TiO2 deposition

First heating of the compact layer over a hot plate : low temperature

Second and final heating - Sintering TiO2 on a muffle furnace : high temperature

Compact TiO2 layer deposited over a TCO for thin-film chalcogenide or Perovskite solar cells.

Talking about strategies for high efficiency kesterite solar cells

2019-08-27T15:40:00.001-05:00

Dr. Edgardo A. Saucedo visits BUAP after the MRS congress in Cancun, Mexico and gives us a motivational talk about kesterites PV technology. He is the leader of the Solar Energy Materials and Systems Group at IREC and leads the European STARCELL project too.

Kesterites are a promising PV material, it's metal elements, Copper, Zinc, and Tin are abundant on earth crust. This material owns a tetragonal lattice similar to commercial PV technology. As Dr. Saucedo said, they come from the royal family of photovoltaics.

Kesterites comes from the royal family of photovoltaics

Source: PV-Education Crystal structure of the royal family of photovoltaics

The pace of research on kesterites has been slow due to the emergence of perovskites who has reached a conversion efficiency of 24%(early 2019) while kesterite holds a record of 12.6% reported by IBM in 2013. As you can see, there is a difference of 6 years between both reports [1].

STARCELL born to push forward kesterites PV technology and it is formed by universities and industrial partners. As you can see in the next image, the project is conceived by institutions which have the infrastructure for developing solar cells. You can read a complete description in the following link (About Starcell-Project)

STARCELL organization structure for CZTS development of solar cells and scale-up to PV modules

Challenges of kesterite technology: Doping and alloying

The main technological challenge of kesterites is their Low Voc. For example, the sulfo-selenide kesterite or CZTSSe has a Voc of 513 mV [2] compared to commercial CIGSe solar cells which reach 734 mV [3]. Dr. Saucedo said that some bulk properties of the kesterite related to recombination process should be enhanced controlling the following techniques:

IFUAP - Physics Institute BUAP (POSDOC)

2019-08-26T07:37:00.000-05:00

Last April 2019, I wrote a project for a postdoctoral stay at IFUAP. This stay will be founded by PRODEP-SEP. The goal is to reinforce the photovoltaic area developing thin-film solar cells based on novel materials. The application specifies a 3-month deadline for a response (late July). However, when the deadline arrives, IFUAP said that this response can spend up to 5-months with no compromise. Therefore, this project can not be started.

All of this is happening due to political reason. When the Mexican government changes most of the funds for public scientific research were frozen until politics trace the new route of investment. Somebodies say that it is due to a re-structure of the funds, but nobody can deny the collateral damage. There are a lot of unemployed people who were founded by Conacyt during their master or a Ph.D. degree.

No matter this situation, I embraced the risk and moved to Puebla City. Here I have been able to meet the researcher, its infrastructure, and the surroundings. BUAP is the Autonomous University of Puebla one of the best of this city. After three weeks, I have been able to assist the weekly seminars (open to the public), interact with bachelors and Ph.D. Students. When I saw for the first time the main IFUAP building, I could understand that the university is in a current expansion. They are building its Rectoria Tower. I'll expect a positive response from IFUAP to be able to do science within collaboration with their specialist.

Meanwhile, let's discover the history of Puebla located in their museums. And of course, prepare a short manual for solar cells design using SCAPS-1D software.

Fig 1: IFUAP - Institute of physics - BUAP (Puebla)

Fig 2: Profile measurements of thin films (co-work and training)

Chemical deposition of antimony sulfide & silver antimony sulfide

2019-08-15T07:13:00.000-05:00

The following photographs show the first 30 minutes of the solution reaction for chemical deposition of antimony sulfide thin films. This material is a p-type semiconductor. It is deposited as an amorphous source (Sb-S). The films have the necessary content to produce an orthorhombic lattice after heating above 250 ºC.

Application

Antimony sulfide is used for the research of thin-film solar cells with the following configuration TCO/CdS/Absorber/BackContact. This film is achieved using the formula reported in the paper I publish during my Ph.D. program (With no AgNO3). Find it here.

For tips about deposition, feel free to write a comment!

[1] J. Capistrán Martínez, P.K. Nair, Photoconductive thin films of AgSbS2 with cubic crystalline structure in solar cells, Physica Status Solidi (a). 212 (2015) 2869–2876. doi:10.1002/pssa.201532496.

Initial deposition condition temperature near 10 ºC

The reaction of the Sb-S solution begins after 10 minutes.

The color of the reaction change completely at 30 minutes, this color will be maintained until the controlled precipitation finish.

After 3-4 hours of deposition, the films look good, there is adherence to the glass substrate and specular reflection in the surface.

Water molecule using Burai 1.3 and Quantum Espresso

2019-07-11T05:47:00.002-05:00

Course: Electronic properties of semiconductors by AB-INITIO

Profesor: Dr. Raciel Jaimes López (Postdoctoral at IER-UNAM)

Simulation of water molecule formation using Burai 1.3 and Quantum Espresso

Viewer by Jmol

Last month I attended the course Electronic properties of semiconductor by AB-Initio at IER-UNAM, on the 1st day we had a quick view about the background of DFT (Density Functional Theory), plane waves and pseudopotentials. During the course, we learn about the open-code Quantum Espresso software which is used for electronic-structure calculation and materials modeling at nano-scale.

Here I share the methodology I follow for the example water-molecule

Install BURAI1.3 on MAC (includes Quantum-Espresso)

https://burai.readthedocs.io/en/latest/install/download.html

Install MPI for MAC

https://burai.readthedocs.io/en/latest/install/setting.html

Open BURAI and choose examples/XYZ: Water molecule (H2O.xyz)