Layer-by-layer fabrication of organic photovoltaic devices: material selection and processing conditions

Abstract

Layer-by-layer (LbL) processing, otherwise known as sequential deposition, is emerging as the most promising strategy for fabrication of active layers in organic photovoltaic (OPV) devices on both laboratory and industrial scales.

Multi‐Functional Solid Additive Induced Favorable Vertical Phase Separation and Ordered Molecular Packing for Highly Efficient Layer‐by‐Layer Organic Solar Cells

“…Compared with the widely applied BHJ approach, the layerby-layer (LBL) structures via sequential depositing the donor and acceptor layers favor the formation of a p-i-n like structure, which has been regarded as a promising approach for OPV large-scale printing. [23][24][25][26][27][28][29] The construction of such morphology provides preferable vertical component distribution, leading to efficient charge collection at the corresponding electrodes. To Layer-by-layer (LBL) deposition strategy enabling favorable vertical phase distributions has been regarded as promising candidates for constructing high-efficient organic photovoltaic (OPV) cells.…”

Efficient semi-transparent organic solar cells enabled by a quasi-heterojunction active layer structure

“…Two-step sequential deposition (SD) of the donor and acceptor has been used to fabricate OSCs since the donor layer and acceptor layer can be optimized independently. 25–27 A quasi-heterojunction of a SD-type active layer has desired vertical component distribution of the donor and acceptor, which is beneficial to charge collection. 28,29 More recently, the PCE of SD-type OSCs has been reported to be over 18%, which is comparable to the results of BHJ-type OSCs.…”

Baseplate Temperature‐Dependent Vertical Composition Gradient in Pseudo‐Bilayer Films for Printing Non‐Fullerene Organic Solar Cells

“…[12,31] In short, these advantages have resulted in significant interest in the SD technique and its potential to displace conventional BHJ as the dominant filmforming process for large-scale OSC manufacturing. [30,32] Although suitable vertical phase separation [11][12][13]30] can be easily achieved by SD processing approach, the lack of control over vertical composition gradient and molecular crystallinity at the time of sequential blade-processing deposition probably remains a key limitation. Notably, unlike the development of a vertical composition gradient in a BHJ blend film during rapid solvent evaporation strongly and simultaneously affected by multiple key parameters, including the miscibility (or interaction parameter χ) of the D/A components, [33] the molecular crystallinity, [4] free-surface or interfacial surface energy, [34,35] and the abovementioned processing conditions, [15,16,36] baseplate and solvent temperature, etc., [7,[37][38][39] the major factor that affected the vertical phase separation in a PPH layer is the baseplate temperature during the printing technique progress.…”