Improvement of power conversion efficiency by a stepwise band-gap structure for silicon quantum dot solar cells

Abstract

As a promising next-generation solar cell, the power conversion efficiency of a silicon quantum dot (Si-QD) solar cell is still low. In this work, the band-gap structure of a Si-QD layer was modified to improve the power conversion efficiency of a Si-QD solar cell. A stepwise band-gap Si-QD (SB Si-QD) layer with a high bandgap top layer (about 2.22 eV) and a low band-gap bottom layer (about 1.98 eV) was grown on a Si (100) substrate. The open circuit voltage and short circuit current were improved by band-gap engineering of the Si-QD absorption layer. As a result, the power conversion efficiency of the SB Si-QD solar cell increased from 16.50% to 17.50%, compared to that of a Si-QD solar cell with a uniform band gap. This results will provide a guide to design advanced Si-QD solar cells by considering the band-gap structure in the Si-QD absorption layer.

An explanation for the non-monotonic temperature dependence of the photoluminescence spectral features of self-organized InAs QDs

“…The main physical property of these materials is to have all the photocarriers distributed among discrete levels, which drastically ameliorates the electronic and optical efficiencies of the optoelectronic devices and intermediate band solar cells [4][5][6]. On the other hand, in order to attain high power conversion efficiency in QD-based photovoltaic systems, the photo-excitation inside the solar cell structures must be extended [7,8].…”

Thermal Disproportionation for the Synthesis of Silicon Nanocrystals and Their Photoluminescent Properties

“…A novel stepwise bandgap SiNCs layer structure was put forward, which was composed of a top layer (high bandgap) and a bottom layer (low bandgap). This combination improved charge transfer efficiency, and hence the power conversion efficiency of SiNCs solar cell was also increased from 16.50 to 17.50% compared to the efficiency of solar cell with uniform bandgap structure (Kwak et al, 2017;Kwak et al, 2020). In addition to the PL intensity, PL line width also played a critical role in light-emitting devices.…”