Solution-processed intermediate-band solar cells with lead sulfide quantum dots and lead halide perovskites.

Hosokawa, Hiroji; Tamaki, Ryo; Sawada, Takuya; Okonogi, Akinori; Sato, Haruyuki; Ogomi, Yuhei; Hayase, Shuzi; Okada, Yoshitaka et al. · Nat Commun · 2019

basic_science · Level V

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Abstract

The intermediate-band solar cell (IBSC) with quantum dots and a bulk semiconductor matrix has potential for high power conversion efficiency, exceeding the Shockley-Queisser limit. However, the IBSCs reported to date have been fabricated only by dry process and their efficiencies are limited, because their photo-absorption layers have low particle density of quantum dots, defects due to lattice strain, and low bandgap energy of bulk semiconductors. Here we present solution-processed IBSCs containing photo-absorption layers where lead sulfide quantum dots are densely dispersed in methylammonium lead bromide perovskite matrices with a high bandgap energy of 2.3 eV under undistorted conditions. We confirm that the present IBSCs exhibit two-step photon absorption via intermediate-band at room temperature by inter-subband photocurrent spectroscopy.