Structural and Electronic Properties of Semiconductor‐Sensitized Solar‐Cell Interfaces

Abstract

A recent study has reported a power‐conversion efficiency of 5.1% for solar cells employing mesoporous TiO2 films sensitized with quantum dots of stibnite (Sb2S3). Here, a first‐principles atomic‐scale investigation of the interface between TiO2 and Sb2S3 is presented. The proposed atomistic interface model is free of defects, and the calculated energy‐level alignment at the interface indicates that the ideal open‐circuit voltage is as high as 1.6 V. Films sensitized with the isostructural compounds bismuthinite (Bi2S3) and antimonselite (Sb2Se3), which exhibit band gaps closer to the ideal Shockley–Queisser value are also examined. In the case of Bi2S3 the calculations indicate that the lowest unoccupied molecular orbital is too low in energy to inject electrons into TiO2, in agreement with experimental data. For antimonselite (Sb2Se3) the calculations predict a type‐II heterojunction with TiO2, and suggest that Sb2Se3 sensitization may lead to higher power conversion efficiencies than found in the TiO2/Sb2S3 system.

First-principles study of the lattice dynamics of Sb2S3

“…So far, much focus has been placed on the synthesis and electronic properties [12][13][14][15] of Sb 2 S 3 . To complement these known aspects, we present here a study of the lattice vibrational properties of Sb 2 S 3 using density-functional theory (DFT).…”

Thin-film Sb2Se3 photovoltaics with oriented one-dimensional ribbons and benign grain boundaries

“…Like CdTe, but in contrast with CIGS and CZTS, Sb2Se3 is a simple binary compound with fixed phase and stoichiometry. It has a very strong absorption coefficient (>10 5 cm -1 at short wavelengths) and its bandgap is ~1.1 eV 17,18 , optimal for single-junction solar cells. The constituents of Sb2Se3 are non-toxic and low in cost (Sb has similar cost to Cu), and, as we proceed to show herein, Sb2Se3 films are produced using minimal energy, enabling in principle a low energy-payback time for a solar cell 19 .…”

Sb2Se3 sensitized heterojunction solar cells

“…Besides, the relative positions of the conduction band edges of nanostructured Sb 2 Se 3 and SnO 2 display favourable energetics for electron transfer at their interface [12]. In addition, theoretical calculations performed by Giustino et al [9,10] demonstrated the improved performance of Sb 2 Se 3 -based devices compared to Sb 2 S 3 based cells, and suggested Sb 2 Se 3 as a promising candidate for achieving 20 % PCE. In spite of these advantages, Sb 2 Se 3 -based solar cells have rarely been experimentally demonstrated.…”

“…Among these materials, antimony selenide (Sb 2 Se 3 ) is a group V 2 -VI 3 layered structured direct band gap semiconductor with orthorhombic crystal structure [7]. Sb 2 Se 3 displays a narrow band gap of 1.1-1.3 eV, [8][9][10] which approaches the ideal Shockley-Queisser value, [11] and has the ability to extend light harvesting over the near-IR region up to approximately 1000 nm. Besides, the relative positions of the conduction band edges of nanostructured Sb 2 Se 3 and SnO 2 display favourable energetics for electron transfer at their interface [12].…”