Enhanced Charge Transport via Metallic 1T Phase Transition Metal Dichalcogenides‐Mediated Hole Transport Layer Engineering for Perovskite Solar Cells

Abstract

In perovskite photovoltaic cells having a p‐i‐n structure, the hole transport layer (HTL) plays an important role in device performance because it has a direct impact on the crystallinity of overlying perovskite films as well as the interfacial charge transport. Poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT : PSS) has been widely used as an HTL owing to its desirable electrical and optical properties with solution processability. However, improving the functionality of PEDOT : PSS still requires broad attention to maximize the related solar cell performance, such as further enhancing the electrical properties to achieve better charge transport at the electrode and photoactive layer interface and reducing the nucleation energy barrier to improve crystallinity of the overlying perovskite films. Two‐dimensional transition metal dichalcogenides (TMDs) have been studied in various optoelectronic devices owing to their intriguing optoelectric features. In this study, tungsten diselenide (WSe2) was implemented with PEDOT : PSS to enhance the performance in p‐i‐n perovskite solar cells. The incorporation of WSe2 into PEDOT : PSS led to improved charge transport at the photoactive layer and electrode interface as well as the favorable growth of the perovskite crystal. As a result, a notable improvement in the performance of the solar cell having the WSe2‐mediated PEDOT : PSS HTL was observed in comparison to that of the PEDOT : PSS only device, which had power conversion efficiencies of 16.3% and 13.8%, respectively. The facile approach proposed in this study may be readily extended to various other perovskite‐based optoelectronic devices beyond solar cells toward the enhancement of device functionality.

Inverted perovskite solar cells with enhanced lifetime and thermal stability enabled by a metallic tantalum disulfide buffer layer

“…26 Few-layer akes of SnS 2 were used as ETL material in planar PSC structures, exhibiting PCE values up to 20.1%, 27 while WSe 2 interlayer over PEDOT:PSS was reported to increase the PCE from 13.8% to 16.2%. 28 Finally, inverted PSCs were fabricated through the employment of MoSe 2 as HTL 29,30 or as buffer layer. 31 Differently from the most investigated TMDs, group-V TMDs (e.g., TaS 2 , NbS 2 and VS 2 ) can be found in metal-like phases 32,33 such as 2H-, 3R-and 6R polytypes for Nb-or Ta-based TMDs, 34,35 and 1T-polytypes for V-based TMDs.…”

Role of graphene and transition metal dichalcogenides as hole transport layer and counter electrode in solar cells

“…32,[37][38][39][40] For instance, owing to the remarkable features of TMDCs in PV devices, Choi et al utilized tungsten diselenide (WSe 2 ) as hole transport layer to boost the performance of perovskite SCs. 41 The resulted device showed a PCE of 16.3%, which provided a new route to enhance the device functionality in PV technology. By applying mechanical stress 42 and alloy formation such as Mo 1−x W x S 2 43,44 the band gap, electron affinity, and ionization potential of TMDCs can be tailored.…”

“…Moreover, the direct band gap, excellent harvesting of light, and high mobility make TMDCs a promising material for highly efficient PV devices . For instance, owing to the remarkable features of TMDCs in PV devices, Choi et al utilized tungsten diselenide (WSe 2 ) as hole transport layer to boost the performance of perovskite SCs . The resulted device showed a PCE of 16.3%, which provided a new route to enhance the device functionality in PV technology.…”

Hybrid MoS2/PEDOT:PSS transporting layers for interface engineering of nanoplatelet-based light-emitting diodes

“…[34,37,38] An alternative strategy consists of mixing PEDOT:PSS with TMDs. This approach has been successfully applied to solar cells, leading to higher performance, [39,40,41,42 ] and to other kind of devices. [43] Nonetheless, only few works implement this scheme on LEDs, but the low concentration of exfoliated MoS2 used (~ 0.5 mg mL -1 ) did not allow to have a fair comparison with the reference device and/or UV-ozone irradiation treatment was still needed.…”