Organic Planar Heterojunctions: From Models for Interfaces in Bulk Heterojunctions to High‐Performance Solar Cells

Abstract

Recent progress regarding planar heterojunctions (PHJs) is reviewed, with respect to the fundamental understanding of the photophysical processes at the donor/acceptor interfaces in organic photovoltaic devices (OPVs). The current state of OPV research is summarized and the advantages of PHJs as models for exploring the relationship between organic interfaces and device characteristics described. The preparation methods and the characterization of PHJ structures to provide key points for the appropriate handling of PHJs. Next, we describe the effects of the donor/acceptor interface on each photoelectric conversion process are reviewed by examining various PHJ systems to clarify what is currently known and not known. Finally, it is discussed how we the knowledge obtained by studies of PHJs can be used to overcome the current limits of OPV efficiency.

The Dawn of Single Material Organic Solar Cells

“…Thermal treatment at 150 °C for 20 min increased J sc to 2.57 mA cm −2 and PCE to 0.49%. [81] More recently, the same group has reported the synthesis of another series of parent "double-cable" polymers with poly(DTBDT) as supporting backbone and pendant PBI acceptor groups (10). [79] The degree of polymerization estimated from 1 H NMR data was limited to 3-4 units.…”

Intermolecular Arrangement of Fullerene Acceptors Proximal to Semiconducting Polymers in Mixed Bulk Heterojunctions

“…[12] There have been substantial advances in understanding the mechanism of OPVs.I th as been shown that the properties of the organic interfaces strongly affect the charge separation and recombination processes. [23][24][25][26] Taken together,t hese studies suggest that precise control of the BHJ structure at the molecular level could be crucial to improving the performance of OPVs further.T he interfacial structures of mixed BHJs,however,are difficult to analyze at the molecular scale because of the limitations of analytical methods. [14][15][16][17][18][19] Therefore,t he spatial arrangement of the donor and acceptor can strongly affect the photophysical and electronic processes in OPVs,a s suggested by theoretical calculations [20][21][22] and experimental studies using planar heterojunctions as model systems.…”

“…[13] Thec hargetransfer (CT) state at the interface has as trong correlation with the OPV performance. [23][24][25][26] Taken together,t hese studies suggest that precise control of the BHJ structure at the molecular level could be crucial to improving the performance of OPVs further.T he interfacial structures of mixed BHJs,however,are difficult to analyze at the molecular scale because of the limitations of analytical methods. [23][24][25][26] Taken together,t hese studies suggest that precise control of the BHJ structure at the molecular level could be crucial to improving the performance of OPVs further.T he interfacial structures of mixed BHJs,however,are difficult to analyze at the molecular scale because of the limitations of analytical methods.…”

Supramolecular Assemblies of Cucurbiturils with Photoactive, π‐conjugated Chromophores

“…[1][2][3][4][5][6] However, there are some drawbacks that should be overcome in order to utilize them in a wider context including stability (chemical, thermal, photo), solubility, poor optical performance (low quantum yields, low lifetime) due to aggregation. Photoactive, p-conjugated chromophores have many important applications in the areas of sensing, catalysis, lasers, imaging, theranostics and photonics.…”