[6a-A204-1~10] 16.3 Bulk, thin-film and other silicon-based solar cells

[6a-A204-8] Nonequilibrium theory of solar cells including finite thermalization and extraction time

〇Kenji KAMIDE¹, Toshimitsu Mochizuki¹, Hidefumi Akiyama², Hidetaka Takato¹ (1.AIST, 2.ISSP, Univ. Tokyo)

Keywords:solar cell, SQ limit, non-equilibrium theory

Detailed balance limit of solar cell conversion efficiency, 29.5 % for single junction planer Si cells (1 sun, AM0), is known as the SQ limit given by Shockley and Queisser. While their theory is based on several assumptions, the requirements in real devices are not fully discussed. Here we focus on their two assumptions: (1) Photo-generated carriers lose the kinetic energy via phonon emission and fully relax to the band bottom in a moment. (2) Photo-generated carriers are extracted to carrier reservers in a moment. Using a theoretical model accounting for the carrier relaxation and extraction dynamics, we reformulate a nonequilibrium theory for solar cells, which covers both equilibrium (the detailed balance applies) and non-equilibrium regime. Based on our formulation, we address the parameter regime where the conventional SQ theory applies to and what could happen outside the range.