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2024 Absorber texture and the efficiency of polycrystalline thin film CdTe TSF.pdf (7.43 MB)

Absorber texture and the efficiency of polycrystalline thin film CdTe solar cells

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posted on 2024-03-11, 11:46 authored by Vlad Kornienko, Ochai Oklobia, Stuart Irvine, Steve Jones, Amit Munshi, Walajabad Sampath, Ali AbbasAli Abbas, Kieran CursonKieran Curson, Stuart RobertsonStuart Robertson, Yau TseYau Tse, Kurt BarthKurt Barth, Jake BowersJake Bowers, Michael WallsMichael Walls

A range of microstructural changes occur during the deposition and activation of CdTe based thin film solar cells. In particular, the cadmium chloride (CdCl2) activation treatment results in wholesale recrystallisation which transforms the conversion efficiency of the solar cell. One of the noticeable effects is the change of preferred orientation of the CdTe absorber. Highly orientated [111] texture is observed in as deposited or under-treated CdTe based devices. Optimized activation results in a more randomized texture and the [111] preferred texture component is significantly weakened. In this paper we use Electron Backscatter Diffraction to characterise absorber cross-sections. The focus is on how randomization of the absorber texture reflects device performance. We have had access to a range of CdTe devices using a variety of deposition techniques. We have observed a clear pattern that shows that devices with a highly orientated [111] texture have poor efficiency. Devices with a randomized texture have much higher efficiency. Here we illustrate this empirical correlation using devices deposited by Metal Organic Chemical Vapour Deposition with a range of efficiencies from 13.1 % to 17 %. We have also included the analysis of an absorber from a 18.7 % high efficiency CdSeTe/CdTe device to show that texture is similarly important in these advanced devices. We have been able to quantify the effect of texture by using multiples of uniform density or (MUD) values from the inverse pole figures. MUD figures close to 1 correlate with highest efficiency. Although the random texture of the absorber microstructure is only one of several important process factors, it appears to be a necessary feature for highest efficiency CdTe-based polycrystalline solar cells.

Funding

Doped emitters to unlock lowest cost solar electricity

Engineering and Physical Sciences Research Council

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Doped Emitters to Unlock Lowest Cost Solar Electricity

Engineering and Physical Sciences Research Council

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Underpinning Multi-User Equipment

Engineering and Physical Sciences Research Council

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History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering
  • Mechanical, Electrical and Manufacturing Engineering

Department

  • Materials

Research Unit

  • Centre for Renewable Energy Systems Technology (CREST)

Published in

Thin Solid Films

Volume

793

Publisher

Elsevier BV

Version

  • VoR (Version of Record)

Rights holder

© The Authors

Publisher statement

This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Acceptance date

2024-02-23

Publication date

2024-02-24

Copyright date

2024

ISSN

0040-6090

eISSN

1879-2731

Language

  • en

Depositor

Prof Michael Walls. Deposit date: 8 March 2024

Article number

140277

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