Showing posts with label review. Show all posts
Showing posts with label review. Show all posts

October 14, 2019

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


Authors: P. K. Nair,  JosĂ© Diego Gonzaga SĂĄnchez, Laura Guerrero MartĂ­nez, Perla YoloxĂłchitl GarcĂ­a Ayala, Ana Karen MartĂ­nez Peñaloza, Alessandra Beauregard LeĂłn, Yareli ColĂ­n GarcĂ­a, JosĂ© 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 ÂșC) 

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. 


May 23, 2019

Paper: Kesterite solar cell with 12.6% efficiency

Cited 1900 times (May 2019) -  Journal: Advanced Energy Materials
Link: Device Characteristics of CZTSSe Thin-Film Solar Cells with 12.6% Efficiency 

Challenge:

Decrease Voc deficit of current CZTSSe (1.13 eV) solar cells.

The reported device has 12.6 % efficiency with  500 mV of Voc from a maximum of 820 mV calculated by SQ analysis. Therefore if Voc is enhanced the device would get better. But to achieve this enhancement we should understand the dependence between minority carrier lifetime and recombination process.

Highlights:

  • Kesterites are fabricated with Cu-poor and Zn-rich content
  • Understand:  junction CdS/CZTSSe, current collection and recombination mechanism
  • Defects impact the minority carrier lifetime and thus collection length (Lc = Xp + Ln). 
  • Lifetime (”n, ”p, defects)  
Characterization Techniques:

  • SIMS - Analysis of carbon and oxygen concentration 
  • SEM - Morphology (Front and cross section)
  • EDX - Composition (Cu, Zn, Sn) profiling 
  • JV - Basic parameters (Voc, Jsc, FF, Eff) 
  • Sites method: Diode parameter - Ideality factor, Saturation current Jo, Rs, Rsh
  • CV - Concentration and nature of defects: Sensitive to interface traps
  • DLCP - (Drive level capacitance profile): Sensitive to bulk defects
  • JVT - Activation energy of the main recombination process
  • EQE - External quantum efficiency: Eg 
  • UV-VIS-NIR: Optical reflectance
  • EBIC - Indicate collection region for minority carriers. 
Device fabrication:

  • CZTSSe fabricate by pure-solution method (Hydrazine)
  • Back contact: Molybdenum (500 nm) 
  • Mo(S,Se)2:  approx (180 nm)
  • Absorber: CZTSSe (2 ”m)
  • Buffer: CdS (25 nm)
  • Window: ZnO/ITO (10 nm / 50 nm)
  • Grid: Ni/Al (2 ”m)
  • Anti-reflective: MgF2
  • Total area: 0.42 cm2 defined by mechanic scribe

April 22, 2019

Review of the STARCELL project publications

 This project is developed in the European Union due to photovoltaics is one of the main technologies necessary to achieve the targets of EU Energy Roadmap 2050.  For me, it is interesting to know the state of the art of this material as a prospect for a postdoctoral stay in 2019-2020.

  • This topic is highly related to solar cell development and innovation.
  • One key feature is the development of thin film photovoltaics using flexible substrates



Webpage Snapshot (April 22nd, 2019) - STARCELL Project 

STARCELL aims to substitute two critical raw materials (In and Ga) used in conventional thin film photovoltaic (PV) technologies, via the introduction of sustainable kesterite (Cu
2ZnSn(S,Se)4 - CZTSSe) semiconductors. (Project STARCELL Objective)

Publications:


[1] S. Giraldo, E. Saucedo, M. Neuschitzer, F. Oliva, M. Placidi, X. AlcobĂ©, V. Izquierdo-Roca, S. Kim, H. Tampo, H. Shibata, A. PĂ©rez-RodrĂ­guez, P. Pistor, How small amounts of Ge modify the formation pathways and crystallization of kesterites, Energy Environ. Sci. 11 (2018) 582–593. doi:10.1039/c7ee02318a. (Link)(Cited by 22)

[2] S.G. Haass, C. Andres, R. Figi, C. Schreiner, M. BĂŒrki, Y.E. Romanyuk, A.N. Tiwari, Complex Interplay between Absorber Composition and Alkali Doping in High-Efficiency Kesterite Solar Cells, Adv. Energy Mater. 8 (2018) 1–9. doi:10.1002/aenm.201701760. (Link) (Cited by 11)


[3] C.J. Hages, A. Redinger, S. Levcenko, H. Hempel, M.J. Koeper, R. Agrawal, D. Greiner, C.A. Kaufmann, T. Unold, Identifying the Real Minority Carrier Lifetime in Nonideal Semiconductors: A Case Study of Kesterite Materials, Adv. Energy Mater. 7 (2017) 1–10. doi:10.1002/aenm.201700167. (Link) (Cited by )


[4] J. MĂĄrquez, H. Stange, C.J. Hages, N. Schaefer, S. Levcenko, S. Giraldo, E. Saucedo, K. Schwarzburg, D. Abou-Ras, A. Redinger, M. Klaus, C. Genzel, T. Unold, R. Mainz, Chemistry and Dynamics of Ge in Kesterite: Toward Band-Gap-Graded Absorbers, Chem. Mater. 29 (2017) 9399–9406. doi:10.1021/acs.chemmater.7b03416. (Link