Tetra‐Propyl‐Substituted Copper (II) Phthalocyanine as Dopant‐Free Hole Transporting Material for Planar Perovskite Solar Cells

Abstract

Solution‐processed hole transporting materials (HTMs) that are dopant‐free show promise for use in low‐cost, high‐performance perovskite solar cells (PSCs). In this study, a new HTM of copper (II) phthalocyanine with tetra‐propyl‐substituted function groups (CuPrPc) is reported. It is found that CuPrPc could form face‐on molecular orientation when spin‐coated on perovskite, resulting in high hole mobility and hydrophobic surface. These properties are more favorable for hole transport and moisture resistance applications in PSCs. Solution‐processed planar PSCs utilizing CuPrPc as HTM are fabricated and tested. PSC with CuPrPc exhibited highest power conversion efficiency of 17.8%. Furthermore, beneficial from the hydrophobic nature of CuPrPc, the devices with CuPrPc as HTM show improved stability and retain over 94% of their initial efficiency even after storage in humidity about 75% for 800 h without encapsulation, which is much better than the performance of PSCs based on Spiro‐OMeTAD HTM.

Dopant‐Free Hole Transporting Materials for Perovskite Solar Cells

“…An average PCE of 17.0 ± 0.5% and a highest PCE of 17.8% were achieved for PSC devices fabricated by a simple solution process using CuPrPc as a dopant‐free HTM. Furthermore, beneficial from the hydrophobic nature of CuPrPc, the devices with CuPrPc as HTM show improved stability and retain over 94% of their initial efficiency even after storage in humidity about 75% for 800 h without encapsulation, which is much better than the performance of PSCs based on Spiro‐OMeTAD HTM …”

High‐Performance Inverted Planar Perovskite Solar Cells Enhanced by Thickness Tuning of New Dopant‐Free Hole Transporting Layer

“…As literatures reported, HTMs can be mainly divided into two types based on their chemical structures. One is that those containing rigid spiro units as cores (such as sprio‐type fluorine, triptycene, and their derivatives), another one is those containing planar units as cores (such as thiophenyl, truxene, phthalocyanine units and other π‐conjugated units, and so on). However, both HTMs have their advantages and limitations.…”

Dopant‐Free Hole‐Transporting Layer Based on Isomer‐Pure Tetra‐Butyl‐Substituted Zinc(II) Phthalocyanine for Planar Perovskite Solar Cells

“…Solution processable‐substituted MPcs brought easy deposition methods with lower production costs for perovskite device. In our previous work, tetra‐propyl‐substituted CuPc is used as dopant‐free HTM in a planar‐structured PSC, reaching to a PCE as high as 17.8%, with an improved stability against humidity …”