Trade‐Offs in Thin Film Solar Cells with Layered Chalcostibite Photovoltaic Absorbers

Abstract

Discovery of novel semiconducting materials is needed for solar energy conversion and other optoelectronic applications. However, emerging lowdimensional solar absorbers often have unconventional crystal structures and unusual combinations of optical absorption and electrical transport properties, which considerably slows down the research and development progress. Here, the effect of stronger absorption and weaker carrier collection of 2D-like absorber materials are studied using a high-throughput combinatorial experimental approach, complemented by advanced characterization and computations. It is found that the photoexcited charge carrier collection in CuSbSe 2 solar cells is enhanced by drift in an electric field, addressing a different absorption/collection balance. The resulting drift solar cells efficiency is <5% due to inherent J SC /V OC trade-off, suggesting that improved carrier diffusion and better contacts are needed to further increase the CuSbSe 2 performance. This study also illustrates the advantages of high-throughput experimental methods for fast optimization of the optoelectronic devices based on emerging low-dimensional semiconductor materials.

Simulation studies on photovoltaic response of ultrathin CuSb(S/Se) 2 ternary compound semiconductors absorber‐based single junction solar cells

“…The observed high absorption coefficient for the materials is in accordance with the previously reported experimental values . The respective conduction and valence band density of states are calculated as , where N C,V is the density of states in respective (C, conduction; V, valence) bands, K is the Boltzmann constant, m e and m * e,h is electron mass and the respective carrier effective mass, and h is planks constant . The values of carrier effective masses are used from reported experimental data.…”

“…CuSb(S/Se) 2 absorber layer–based solar cells adopt CIGS or CZTS absorber–based solar cell device structures . The schematic of AZO/i‐ZnO/n‐CdS/CuSb(S/Se) 2 /Back contact heterostructure device considered in this simulation is shown in Figure 1A.…”

“…CuSb(S/Se) 2 absorber layer-based solar cells adopt CIGS or CZTS absorber-based solar cell device structures. 17 The schematic of AZO/i-ZnO/n-CdS/CuSb(S/Se) 2 /Back contact heterostructure device considered in this simulation is shown in Figure 1A. Here, n-CdS is chosen as the heterojunction partner with CuSb(S/Se) 2 absorber layer forming n-p heterojunction interface that collects photogenerated charge carriers.…”

“…where N C,V is the density of states in respective (C, conduction; V, valence) bands, K is the Boltzmann constant, m e and m* e,h is electron mass and the respective carrier effective mass, and h is planks constant. 17,18 The values of carrier effective masses are used from reported experimental data. The other materials physical properties and parameters are summarized in Table 1 and used for computing the photovoltaic response of the devices under considerations.…”

Accelerated Optimization of TiO2/Sb2Se3 Thin Film Solar Cells by High‐Throughput Combinatorial Approach

“…We believe the combinatorial strategy reported here, as well as its successful demonstration in CuSbSe 2 photovoltaics very recently, [12] should be widely implemented in the research on emerging thin film photovoltaics to speed up the development of this very promising field. Highthroughput optimization of TiO 2 and Sb 2 Se 3 film thickness, as well as the postannealing temperature, were achieved by introducing variable gradient in a single batch.…”