On the origin of tail states and VOC losses in Cu(In,Ga)Se2

Fuente: arXiv
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Main Authors: Ramírez, Omar, Nishinaga, Jiro, Dingwell, Felix, Wang, Taowen, Prot, Aubin, Wolter, Max Hilaire, Ranjan, Vibha, Siebentritt, Susanne
Format: Preprint
Published: 2022
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author Ramírez, Omar
Nishinaga, Jiro
Dingwell, Felix
Wang, Taowen
Prot, Aubin
Wolter, Max Hilaire
Ranjan, Vibha
Siebentritt, Susanne
author_facet Ramírez, Omar
Nishinaga, Jiro
Dingwell, Felix
Wang, Taowen
Prot, Aubin
Wolter, Max Hilaire
Ranjan, Vibha
Siebentritt, Susanne
contents The detrimental effect of tail states on the radiative and non-radiative voltage loss has been demonstrated to be a limiting factor for the open circuit voltage in Cu(In,Ga)Se2 solar cells. A strategy that has proven effective in reducing tail states is the addition of alkali metals, the effect of which has been associated with the passivation of charged defects at grain boundaries. Herein, tail states in Cu(In,Ga)Se2 are revisited by studying the effect of compositional variations and alkali incorporation into single crystals. The results demonstrate that alkalis decrease the density of tail states despite the absence of grain boundaries, suggesting that there is more to alkalis than just grain boundary effects. Moreover, an increase in doping as a result of alkali incorporation is shown to contribute to the reduced tail states, which are demonstrated to arise largely from electrostatic potential fluctuations and to be determined by grain interior properties. By analyzing the voltage loss in high-efficiency polycrystalline and single crystalline devices, this work presents a model that explains the entirety of the voltage loss in Cu(In,Ga)Se2 based on the combined effect of doping on tail states and VOC.
format Preprint
id arxiv_https___arxiv_org_abs_2212_01603
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle On the origin of tail states and VOC losses in Cu(In,Ga)Se2
Ramírez, Omar
Nishinaga, Jiro
Dingwell, Felix
Wang, Taowen
Prot, Aubin
Wolter, Max Hilaire
Ranjan, Vibha
Siebentritt, Susanne
Materials Science
Applied Physics
The detrimental effect of tail states on the radiative and non-radiative voltage loss has been demonstrated to be a limiting factor for the open circuit voltage in Cu(In,Ga)Se2 solar cells. A strategy that has proven effective in reducing tail states is the addition of alkali metals, the effect of which has been associated with the passivation of charged defects at grain boundaries. Herein, tail states in Cu(In,Ga)Se2 are revisited by studying the effect of compositional variations and alkali incorporation into single crystals. The results demonstrate that alkalis decrease the density of tail states despite the absence of grain boundaries, suggesting that there is more to alkalis than just grain boundary effects. Moreover, an increase in doping as a result of alkali incorporation is shown to contribute to the reduced tail states, which are demonstrated to arise largely from electrostatic potential fluctuations and to be determined by grain interior properties. By analyzing the voltage loss in high-efficiency polycrystalline and single crystalline devices, this work presents a model that explains the entirety of the voltage loss in Cu(In,Ga)Se2 based on the combined effect of doping on tail states and VOC.
title On the origin of tail states and VOC losses in Cu(In,Ga)Se2
topic Materials Science
Applied Physics
url https://arxiv.org/abs/2212.01603