High-Performance Regular Perovskite Solar Cells Employing Low-Cost Poly(ethylenedioxythiophene) as a Hole-Transporting Material

Abstract

Herein, we successfully applied a facile in-situ solid-state synthesis of conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) as a HTM, directly on top of the perovskite layer, in conventional mesoscopic perovskite solar cells (PSCs) (n-i-p structure). The fabrication of the PEDOT film only involved a very simple in-situ solid-state polymerisation step from a monomer 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) made from a commercially available and cheap starting material. The ultraviolet photoelectron spectroscopy (UPS) demonstrated that the as-prepared PEDOT film possesses the highest occupied molecular orbital (HOMO) energy level of −5.5 eV, which facilitates an effective hole extraction from the perovskite absorber as confirmed by the photoluminescence measurements. Optimised PSC devices employing this polymeric HTM in combination with a low-cost vacuum-free carbon cathode (replacing the gold), show an excellent power conversion efficiency (PCE) of 17.0% measured at 100 mW cm−2 illumination (AM 1.5G), with an open-circuit voltage (Voc) of 1.05 V, a short-circuit current density (Jsc) of 23.5 mA/cm2 and a fill factor (FF) of 0.69, respectively. The present finding highlights the potential application of PEDOT made from solid-state polymerisation as a HTM for cost-effective and highly efficient PSCs.

Non‐Conjugated Polymer as an Efficient Dopant‐Free Hole‐Transporting Material for Perovskite Solar Cells

“…Additionally, D–A conjugated polymer dopant‐free HTMs with rigid conjugated backbones are usually difficult to process into good thin films owing to solubility problems. More recently, PTAA derivatives and poly(3,4‐ethylenedioxythiophene) have been developed as efficient dopant‐free polymer HTMs . However, cost‐effective dopant‐free HTMs for PSCs with PCEs up to 16 % remain rare.…”

Perovskite Solar Cells: From the Laboratory to the Assembly Line

“…PSCs have traditionally been fabricated on transparent conducting materials/oxides (TCO) . The most commonly used TCO is fluorine‐doped tin oxide (FTO), a material also used in the mesoporous form in DSSCs .…”

Analysing the Prospects of Perovskite Solar Cells within the Purview of Recent Scientific Advancements

“…Additionally, it is also cheaper and easier to synthesise [62]. Triazatruxene-based Hole transporting materials with 18.3% PCE [63], PTAA with max PCE of 12% [64], poly (3,4-ethylenedioxythiopene) PEDOT with 17% PCE [65], Spiro-Phenylpyrazole/Fluorine with 14.2% [66], conjugated polyelectrolytes with 12%+ [67], and MEH-PPV and P3HT with 9.65% [68] are other hole-transporting materials which have been successfully investigated.…”