Performance of Bulk Heterojunction Solar Cells Fabricated Using Spray-Deposited Poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]/[6,6]-Phenyl C71 Butyric Acid Methyl Ester Blend Active Layers

Table 1

Root means square, peak-valley value of active layers, and power conversion efficiency of photovoltaic devices fabricated using the active layers with and without TiO𝑥 layer.

Method of preparation	Active layer	RMS; (nm)	Peak-valley value; (nm)	PCE; (%)
Spray coating	Without TiO𝑥	0.56	4.32	1.76
	With TiO𝑥	0.47	5.47	4.01
Spin coating	With TiO𝑥	0.69	7.08	3.56