Shallow defects levels and extract detrapped charges to stabilize highly efficient and hysteresis-free perovskite photovoltaic devices

Reduced trap density and mitigating the interfacial losses by placing 2D dichalcogenide material at perovskite/HTM interface in a dopant free perovskite solar cells

“…[3,4] The open circuit voltage (Voc) of the devices can easily diminish with a lack of charge-density build up and pulling down the quasi-Fermi level splitting due to non-radiative carrier recombination centers that arises from electronic trap states through crystallographic defects and higher-dimensional defects such as grain boundaries. [5,6] Furthermore, these defect sites facilitate nucleating sites for degradation, which annihilate the operation lifetime of the solar cells. [5,7] Even though the numerous endeavours have been directed towards the development of materials to passivate specific defects, most of the additives militate against the PCE enhancement.…”

“…[5,7] Even though the numerous endeavours have been directed towards the development of materials to passivate specific defects, most of the additives militate against the PCE enhancement. [6,8] On the other hand, photo-generated carriers should be extracted efficiently to avoid the generation of new defects as the active layer i.e. perovskite associated with the low defect formation energy.…”

“…perovskite associated with the low defect formation energy. [6] The extrinsic environmental condition, i.e., light intensity, electric field, and temperature during device operation can promote the natal local defects towards the degradation of the active layer, thus it is paramount to extract the untrapped and detrapped carriers promptly to militate charge accumulation and recombination. [6,9,10] The apparent J-V hysteresis and poor stability originate not only from the defective active layer and disordered charge transport, but also from perovskite/charge transport layer (CTL) interfaces, and charge extracting materials.…”

“…[6] The extrinsic environmental condition, i.e., light intensity, electric field, and temperature during device operation can promote the natal local defects towards the degradation of the active layer, thus it is paramount to extract the untrapped and detrapped carriers promptly to militate charge accumulation and recombination. [6,9,10] The apparent J-V hysteresis and poor stability originate not only from the defective active layer and disordered charge transport, but also from perovskite/charge transport layer (CTL) interfaces, and charge extracting materials. [4,11,12] The interface between the hole transport material (HTM) and the perovskite remains the vulnerable part in the device for stability as trapped charges at the interface between perovskite and charge extraction layer are responsible for the irreversible degradation caused by moisture.…”

Encapsulation for perovskite solar cells

“…Organometal halide perovskites with promising electro-optical properties have been emerged as leading semiconducting materials for solution-processed optoelectronic devices [1][2][3]. Thanks to the great efforts from the photovoltaic community during last decade, the power conversion efficiencies (PCEs) of perovskite solar cells (PVSCs) have risen from 3.8% to 25.2%, surpassing that of polycrystalline silicon solar cells [4,5].…”