InGaP-based InP quantum dot solar cells with extended optical absorption range

Abstract

In the quest for an efficient optical absorption of broad-band solar irradiation, intermediate-band solar cells composed of wide-bandgap semiconductors have attracted attention. In the present study, we developed and investigated the performance of wide-bandgap InGaP-based InP quantum dot (QD) solar cells. The solar cells were fabricated by solid-source molecular beam epitaxy, and their optical absorption range was found to be up to >850 nm, which is larger than the >680 nm optical absorption range of the host InGaP solar cells. Through the measurements of the voltage-dependent quantum efficiency, the photocarriers generated in the InGaP host were determined to be captured into the InP QDs, rather than expelled from the solar cells. The findings of this study highlight the need for the development of an optimized structure of intermediate-band solar cells to mitigate the capture of the photocarriers.

Design and characterization of InGaP-based InP quantum dot solar cells

“…To address the advantages of both a wide-bandgap host and type-II QDs, we have proposed the use of type-II InP QDs in an InGaP host as a wide-bandgap host IB solar cell, 22,23) and demonstrated the extended optical absorption due to the InP QDs. 24) In the InP QD cells, however, the quantum efficiency has decreased in the visible and ultraviolet regions compared with that in the reference InGaP solar cell with no InP QDs, indicating that the shortwavelength light is not absorbed by the host InGaP layer without QDs but the QD layers. 24) This reduced carrier collection behavior has not yet been well investigated.…”

“…24) In the InP QD cells, however, the quantum efficiency has decreased in the visible and ultraviolet regions compared with that in the reference InGaP solar cell with no InP QDs, indicating that the shortwavelength light is not absorbed by the host InGaP layer without QDs but the QD layers. 24) This reduced carrier collection behavior has not yet been well investigated.…”

Investigation of the open-circuit voltage in wide-bandgap InGaP-host InP quantum dot intermediate-band solar cells

“…In order to clarify the advantages of both a wide-bandgap host and type-II QDs, we have proposed the use of type-II InP QDs in an InGaP host 21,22) as a wide-bandgap host IB solar cell 23) and demonstrated the extended optical absorption caused by the InP QDs. 24) However, the feasibility of these InP=InGaP QD solar cells has not yet been well investigated.…”

Estudo De Pontos Quânticos De in as P Ingap Para Compor Uma Célula Solar De Banda Intermediária

“…Considerando o elétron na BC e o buraco na BV, a recombinação do par elétron-buraco acontecerá de forma espacialmente direta, como mostra a figura 2.6. A recombinação espacialmente indireta aumenta o tempo de vida do portador e dificulta a recombinação do par elétron buraco (15), podendo aumentar a eficiência da IBSC.…”

“…Antes de crescer os pontos quânticos propostos de InAsP, realizamos o crescimento de PQ de InP. Por ser uma liga binária e haver na literatura várias referências incluindo medidas de fotoluminescência, fotoluminescência resolvida no tempo e microscopia de força atômica (14) (23) (16) (15), decidimos iniciar o estudo com esses pontos quânticos.…”