Characterization of the Organic Thin Film Solar Cells with Active Layers of PTB7/PC₇₁BM Prepared by Using Solvent Mixtures with Different Additives

Abstract

Organic thin film solar cells (OTFSCs) were fabricated with blended active layers of poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7)/[6,6]-phenyl-C71-butyric (PC71BM). The performances of active layers are prepared in chlorobenzene (CB) with different additives of 1-chloronaphthalene (CN) and 1,8-Diiodooctane (DIO) by a wet process with spin coating technique. The effects of different solvent additives on photovoltaic parameters such as fill factor, short circuit current density, and power conversion efficiency of active layers are reported. The absorption and surface morphology of the active layers are investigated using UV-visible spectroscopy and atomic force microscopy, respectively. The results indicate that structural and morphological changes were induced by the additives with solvent. The current density-voltage (J-V) characteristics of photovoltaic cells were measured under the illumination of simulated solar light with 100 mW/cm2(AM 1.5 G) by an Oriel 1000 W solar simulator. The OTFSCs of PTB7/PC71BM prepared with organic solvent additives of DIO+CN show more improved PCE of 4.96% by spin coating method.

Performance evaluation of PTB7 : PC71BM based organic solar cells fabricated by spray coating method using chlorine free solvent

“…14,[25][26][27]40 To understand the surface morphology of PTB7:PC 71 BM on photovoltaic performance, the active layer are fabricated with spin and spray coating method using non-chlorinated/chlorinated solvent with and without additives DIO. The surface morphology of OTFSCs is controlled by altering blend ratio of donor and acceptor.…”

“…The surface morphology of OTFSCs is controlled by altering blend ratio of donor and acceptor. It also suppresses the recombination charge carrier and improves the device performance, [12][13][14][15]41 The surface roughness of active layers prepared with 3% DIO in XY and CB show R RMS =1.76 and 1.73 nm, respectively. 14,[25][26][27]40 To understand the surface morphology of PTB7:PC 71 BM on photovoltaic performance, the active layer are fabricated with spin and spray coating method using non-chlorinated/chlorinated solvent with and without additives DIO.…”

“…[1][2][10][11][12][13][14] In this most high efficient polymer solar cells are made up of low band-gap polymers with toxic chlorinated solvents due to their high boiling point and solubility. [1][2][10][11][12][13][14] In this most high efficient polymer solar cells are made up of low band-gap polymers with toxic chlorinated solvents due to their high boiling point and solubility.…”

“…Further, the additive DIO has higher boiling point of 169 °C could influence the formation of nanoscale morphology of molecules due to slow evaporation, result in decrease of series resistance and enhance the charge carrier transport properties, as well as increase of shunt resistance due to suppression of charge carrier recombination in the active layer 7,14,15,34. The larger surface aggregates may contain a high concentration of grain boundaries and as a result form photo-carrier recombination centers.…”

A novel donor–donor polymeric dyad of Poly(3‐hexylthiophene‐block‐oligo(anthracene‐9,10‐diyl): Synthesis, solid‐state packing, and electronic properties

“…Polymer‐fullerene based organic solar cells (OSCs) have been promising as a competitive technology for solar energy harvesting due to the unique advantages of being low‐cost, flexible, and lightweight. With the significant improvements in device structure, material composition, and fabrication processes, power conversion efficiencies (PCEs) up to 10 and 12% have been achieved for single layer bulk heterojunction (BHJ) and tandem device architecture, respectively …”