17.6%‐Efficient Quasiplanar Heterojunction Organic Solar Cells from a Chlorinated 3D Network Acceptor

Abstract

Bulk heterojunction (BHJ) organic solar cells (OSCs) have achieved great success because they overcome the shortcomings of short exciton diffusion distances. With the progress in material innovation and device technology, the efficiency of BHJ devices is continually being improved. For some special photovoltaic material systems, it is difficult to manipulate the miscibility and morphology of blend films, and this results in moderate, even poor device performance. Quasiplanar heterojunction (Q‐PHJ) OSCs have been proposed to exploit the excellent photovoltaic properties of these materials. An OSC with BTIC‐BO‐4Cl has a 3D interpenetrating network structure with multiple channels that can facilitate the exciton diffusion and charge transport, and BTIC‐BO‐4Cl is therefore a good candidate for Q‐PHJ OSCs. In this work, a D18:BTIC‐BO‐4Cl‐based Q‐PHJ device is fabricated. The exciton diffusion lengths of D18 and BTIC‐BO‐4Cl are in accord with the requirements of the Q‐PHJ device and the efficiency of Q‐PHJ device is as high as 17.60%. This study indicates that the Q‐PHJ architecture can replace the BHJ architecture to produce excellent OSCs for certain unique donors and acceptors, providing an alternative approach to photovoltaic material design and device fabrication.

Polymer Solar Cells with 18.74% Efficiency: From Bulk Heterojunction to Interdigitated Bulk Heterojunction

“…[36,37] Having the combined advantages of the ease for fabrication characteristic of a PHJ and the large D/A interface area for enhanced exciton dissociation and reduced carrier recombination of a BHJ, the Q-PHJ devices have witnessed even-increasing popularity in recent years. [5,[36][37][38][39][40] Much like the BHJ devices, however, the Q-PHJ solar cells are also suffered from uncontrolled phase separation at the D/A interface (vide supra). [41] By extension of the Q-PHJ concept, one of the ideal morphologies for the active layer in OSCs could be the interdigitated heterojunction (IHJ) structure (Figure 1a, right), where the vertically aligned D nanopillars surrounded by A components (or D nanopores filled with A components), or vice versa.…”

Quasiplanar Heterojunction All‐Polymer Solar Cells: A Dual Approach to Stability

“…Such a structure was defined previously as a quasiplanar heterojunction (Q-PHJ). [32][33][34][35] In the Q-PHJ structure, each component of the bilayer can be separately optimized, which facilitates better control of the active layer morphology and targeted analysis. This kind of structure achieves efficient exciton dissociation without adversely affecting the transports of the carriers in either the polymer donor or acceptor layers, and the carrier recombination could be reduced significantly.…”

Recent Progress in 2D Inorganic/Organic Charge Transfer Heterojunction Photodetectors

“…Except for blends and layered © 2022 Wiley-VCH GmbH heterojunction integrated with 2D, the Quasiplanar heterojunction (Q-PHJ) CT may be another path in the photoconductor with 2D materials. [194] The blending BHJ forms at interface junction and the remaining PHJ specified the built-in field, balancing the trapping and exciton dissociation for high-performance in planar framework. In addition, in the photoconductive framework, more complex situations should be considered to reduce the energy loss and promote transfer efficiency.…”