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Bibliographic Details
Main Authors: Wang, Taowen, Song, Longfei, Bayat, Saeed, Melchiorre, Michele, Valle, Nathalie, Philippe, Adrian-Marie, Defay, Emmanuel, Glinsek, Sebastjan, Siebentritt, Susanne
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2505.03253
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Table of Contents:
  • Reducing the thickness of Cu(In,Ga)Se2 solar cells is a key objective in order to reduce production cost and to improve sustainability. The major challenge for sub-micron Cu(In,Ga)Se2 cells is the recombination at the backside. In standard Cu(In,Ga)Se2 backside recombination is suppressed by a bandgap gradient, acting as a back surface field. This gradient is difficult to maintain in sub-micron thick absorbers. In this study, a hole transport layer passivates the back contact and enables efficient sub-micron Cu(In,Ga)Se2 solar cells without the need of a Ga gradient. The backside passivation by the hole transport layer is as effective as an optimized Ga gradient, resulting in a significant increase in open-circuit voltage by 80 mV in comparison to the reference sample without passivation. Moreover, the hole transport layer exhibits good transport properties, leading to a fill factor as high as 77%. Photoluminescence quantum yield of 0.15% and solar cell efficiency above 18% are demonstrated in sub-micron Cu(In,Ga)Se2 absorbers.