Efficient Hole Extraction from Sb₂S₃ Heterojunction Solar Cells by the Solid Transfer of Preformed PEDOT:PSS Film

Abstract

Here, we report significant improvements of V oc and FF in Sb 2 S 3 quantum dot (QD)-based, solid-state heterojunction solar cells prepared from the solid transfer of preformed PEDOT:PSS hole extraction layers. Despite the moderate optical properties of Sb 2 S 3 QDs, the solid state QD solar cells suffer from poor power conversion efficiency (PCE) resulting from the disappointing V oc and the high series resistance since there is inefficient charge extraction from QDs to the metal top electrode. In order to improve the hole extraction performance, a significantly uniform PEDOT:PSS (poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate)) layer was transferred on the hole transport layer (P3HT, poly(3-hexylthiophene-2,5-diyl)) by using a simple solid-transfer method. In contrast with conventional spin-cast methods, the hydrophilic PEDOT:PSS layer was uniformly coated on the hydrophobic P3HT layer without any significant detriment to P3HT film properties. Due to improved contact surface for the Au top electrode and hole conductance resulting in significantly improved charge extraction, the power conversion efficiency was dramatically enhanced. Furthermore, the thickness of the PEDOT:PSS film was precisely optimized by layer-bylayer solid transfer, and thereby the PCE of the PEDOT:PSS solid-transfer device (30 nm) was improved by 25.

Sb2S3 grown by ultrasonic spray pyrolysis and its application in a hybrid solar cell

“…Theoretical calculations predict an even lower direct optical transition of 1.40 eV [49]. An absorber bandgap of 1.65 eV is found in solar cells with Sb 2 S 3 prepared by ALD [5,19] or in solar cells with Sb 2 S 3 prepared by CBD, as estimated from the photocurrent edge at around 750 nm in the published EQE plots [2,4,6–9 11–12 15–17 40–41 50–53]. Any E g larger than 1.7 eV up to 2.6 eV have been attributed to nanocrystalline Sb 2 S 3 [1,44,54], or to amorphous Sb 2 S 3 [6,44–45 53], while it is also known that contamination, most notably with oxygen, can significantly increase the bandgap value of metal sulfide films [23,55–56].…”

Sb2S3 Solar Cells

“…95 A device with a ZnO-nw/TiO 2 /Sb 2 S 3 / P3HT/Au structure demonstrated 2.3% PCE and V OC of 656 mV under optimized conditions. There were more attempts to modify SSC fabrication stages, such as to use Sb 2 S 3 quantum dots, [96][97][98] pre-formed HTL, 99 and alternative electron transport materials, 100,101 but their performance was significantly lower than that of the SSC device with conventional architecture.…”

Full‐Inorganic Thin Film Solar Cell and Photodetector Based on “Graphene‐on‐Antimony Sulfide” Heterostructure

“…Nevertheless, the PCE of the Sb 2 S 3 solar cells prepared by thermal evaporation is still much lower than the best record (7.5%) that was obtained via the solution method . The PCE of Sb 2 S 3 solar cells may be improved by reducing the hole‐transport resistance in the device, as the recombination of photogenerated electrons and holes mostly occurs in the hole‐transporting layer (HTL) . Generally, in Sb 2 S 3 ‐based solar cells, an electron‐transport layer (ETL) and a HTL are needed to accelerate the separation and transfer of photogenerated electrons and holes.…”