Enhancement in the Efficiency of Sb₂Se₃ Thin‐Film Solar Cells by Increasing Carrier Concertation and Inducing Columnar Growth of the Grains

Abstract

Antimony selenide (Sb2Se3) thin films are attractive light‐absorbing materials for low‐cost and highly efficient thin‐film solar cells. Optimizing columnar growth of the grains and the proper hole concentration will be very helpful for improving the efficiency of Sb2Se3 thin‐film solar cells. In this paper, a monoatomic layer of Al2O3 prepared by the atomic layer deposition (ALD) method is used to increase the hole concentration of the Sb2Se3 film. The increase in the hole concentration is mainly due to the suppression of n‐type defects, such as Vse, or the increase in p‐type defects, such as Vsb. In addition, a simple and environmentally friendly oxygen plasma method is used to modify the CdS film to induce ordered columnar growth of the Sb2Se3 film deposited by the rapid thermal evaporation (RTE) method. Finally, an oxygen plasma treatment on CdS and a monoatomic Al2O3 layer covering the Sb2Se3 was combined to fabricate a solar cell with a new structure, FTO/CdS/P‐Sb2Se3/P+‐Sb2Se3/Al2O3/Au, and its efficiency was increased from 2.48% to 6.7%. These simple, nontoxic, and industrially applicable methods provide potential avenues for preparing low‐cost and highly efficient solar cells.

Review of Recent Progress in Antimony Chalcogenide‐Based Solar Cells: Materials and Devices

“…All these advantages have facilitated the fabrication of high‐quality Sb 2 Se 3 films, leading to obviously increased V OC , J SC , and FF for VTD‐devices. Later, we noticed a report of incorporating monoatomic insulating Al 2 O 3 layer in planar Sb 2 Se 3 solar cells to increase the carrier concentration in Sb 2 Se 3 films . This research proved that the increase in the hole concentration of Sb 2 Se 3 after Al 2 O 3 deposition is mainly attributed to the suppression of n‐type defects, such as Se vacancies and the increase in p‐type defects, such as Sb vacancies.…”

An effective combination reaction involved with sputtered and selenized Sb precursors for efficient Sb2Se3 thin film solar cells

“…where ν 0 is the attempt-to-escape frequency, ω 0 is the inflection point frequency and E a is the defect activation energy that represents the average energetic depth of the defect relative to the valence band maximum (VBM) or conduction band minimum (CBM). [48] The distribution of each defect type was Gaussian fitted using the Kimerling model based on the following equation: [49,50] A small gap of activation energy is observed between the two devices for each defect level and thus it is legal to claim that the defect types are identical for the two devices. It is almost certain that D1 with lowest activation energy could be assigned to V Sb defects, which are shallow acceptors that could be easily formed under Se-rich environments.…”

Boosting VOC of antimony chalcogenide solar cells: A review on interfaces and defects

“…[155][156][157] Inspired by this, a monoatomic Al 2 O 3 film was introduced as a passivation layer by an ALD method (Figure 14F). [158] The hole concentration of the as-deposited Sb 2 Se 3 and after Reproduced with permission. [149] Copyright 2017, Wiley-VCH.…”