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

Konstantinos Chatzimanolis,Nikolaos Tzoganakis,Zdeněk Sofer,Iva Plutnarova,Gabriele Bianca,Leyla Najafi,Reinier Oropesa-Nuñez,Mirko Prato,Beatriz Martín-García,Francesco Bonaccorso,Konstantinos Rogdakis,Dimitris Tsikritzis,Emmanuel Kymakis,Sebastiano Bellani,Marinos Tountas,Miron Krassas

doi:10.1039/d1na00172h

Abstract

Perovskite solar cells (PSCs) have proved their potential for delivering high power conversion efficiencies (PCE) alongside low fabrication cost and high versatility. The stability and the PCE of PSCs can readily be improved by implementing engineering approaches that entail the incorporation of two-dimensional (2D) materials across the device's layered configuration. In this work, two-dimensional (2D) 6R-TaS2 flakes were exfoliated and incorporated as a buffer layer in inverted PSCs, enhancing the device's PCE, lifetime and thermal stability. A thin buffer layer of 6R-TaS2 flakes was formed on top of the electron transport layer to facilitate electron extraction, thus improving the overall device performance. The optimized devices reach a PCE of 18.45%, representing a 12% improvement compared to the reference cell. The lifetime stability measurements of the devices under ISOS-L2, ISOS-D1, ISOS-D1I and ISOS-D2I protocols revealed that the TaS2 buffer layer retards the intrinsic, thermally activated degradation processes of the PSCs. Notably, the devices retain more than the 80% of their initial PCE over 330 h under continuous 1 Sun illumination at 65 °C.

Highlights

Organic–inorganic hybrid perovskite solar cells (PSCs) have revealed their potential as excellent solar energy conversion devices, reaching a power conversion efficiency (PCE) of 25.2%.1 The biggest challenge for the further deployment of PSCs is to attain enhanced lifetime stability without reducing device PCE while up-scaling active area and manufacturing processes.Engineering approaches to tackle these issues include the incorporation of two-dimensional (2D) interlayers (e.g., graphene[2] and transition metal dichalcogenides (TMDs))3 – a process applicable in large-area modules4–6 – the optimization of the doping and surface functionalization of 2D interlayers,[7] as well the possibility of integrating passivation layers[8] such as 2D insulators.[9]
The as-synthesized 6R-TaS2 crystal was characterized by SEMEDS measurements, showing crystal fragment with nearly straight borders and a S : Ta atomic ratio of 1.9 Æ 0.2, which is similar to the values previously measured for TaS2 produced with similar protocols.[42,44,46,47]
Fig. S3a† reports the X-ray diffraction (XRD) pattern of the TaS2 akes in comparison to the one recorded for the native bulk crystal. Both the XRD patterns shows re ections which match those of the 6R phase ((ICSD-52117), a secondary 2H phase (ICSD-68488) coexists with a marginal contribution, as observed by previous studies on 6R-TaS2 polytypes.[42]

Summary

Introduction

Organic–inorganic hybrid perovskite solar cells (PSCs) have revealed their potential as excellent solar energy conversion devices, reaching a power conversion efficiency (PCE) of 25.2%.1 The biggest challenge for the further deployment of PSCs is to attain enhanced lifetime stability without reducing device PCE while up-scaling active area and manufacturing processes.Engineering approaches to tackle these issues include the incorporation of two-dimensional (2D) interlayers (e.g., graphene[2] and transition metal dichalcogenides (TMDs))3 – a process applicable in large-area modules4–6 – the optimization of the doping and surface functionalization of 2D interlayers,[7] as well the possibility of integrating passivation layers[8] such as 2D insulators.[9].

Results

Conclusion