Recent Approaches to Controlling the Nanoscale Morphology of Polymer-Based Bulk-Heterojunction Solar Cells

Abstract

Abstract:The need for clean, inexpensive and renewable energy has increasingly turned research attention towards polymer photovoltaic cells. However, the performance efficiency of these devices is still low in comparison with silicon-based devices. The recent introduction of new materials and processing techniques has resulted in a remarkable increase in power-conversion efficiency, with a value above 10%. Controlling the interpenetrating network morphology is a key factor in obtaining devices with improved performance. This review focuses on the influence of controlled nanoscale morphology on the overall performance of bulk-heterojunction (BHJ) photovoltaic cells. Strategies such as the use of solvents, solvent annealing, polymer nanowires (NWs), and donor-acceptor (D-A) blend ratios employed to control the active-layer morphologies are all discussed.

Influence of donor–acceptor materials on the photovoltaic parameters of conjugated polymer/fullerene solar cells

“…This indicates that an increased roughness is advantageous to device performance. Although as seen from the UV-vis absorption spectra that the absorption decreases as the wt.% age of PC 71 BM is increased, but a higher efficiency is achieved when the blend ratio is 1:4 since PCDTBT:PC 71 BM network forms better and longer connected pathways at this blend ratio [32,33]. Therefore the blend ratio of 1:4 and 12 mg/ml concentration were found to give optimized PCDTBT:PC 71 BM films for organic solar cells.…”

Enhanced photovoltaic performance of ZnO nanorod-based dye-sensitized solar cells by using Ga doped ZnO seed layer

“…The η abs is the ratio of the number of generated excitons to the total incident photons [32], which is limited by the amount of dye adsorption on the ZnO nanorod arrays. It is certain that the abundance of dye loadings could lead to higher η abs .…”

Computation of full polymer-based photovoltaic nanodevices using a parametrized field-based multiscale solar-cell approach

“…For instance, in case of 67 PSCs the photoelectric conversion efficiency currently reaches a 68 maximum of around 9-11% [22][23][24], which is still too low for a 69 wide range of commercial applications. 70 The causes for the low power conversion efficiency of PSCs have 71 primary been associated with loss phenomena of the elementary 72 particles, occurring during the photovoltaic process, such as pho- 73 ton loss, exciton loss and charge carrier loss [25]. Their complex 74 relationship and strong dependence on the structural-dynamical 75 characteristics of the photoactive material have been investigated 76 in various recent experimental [26][27][28][29] and theoretical studies 77 [17,[30][31][32][33][34].…”

“…The new proce-656 dure permitted us to calculate the absorption efficiency (AE),657 representing the number of excitons generated per number of inci-658 dent photons[72], for the bulk heterojunction morphologies and,659 ultimately, to calculate the EQEs of the full polymer nanodevices.660 To this end, we calculated the total AE for each cylinder, using661 the weighted average of the AEs at each wavelength. Then, we 662 determined the overall AE for the whole morphology as a normal 663 average of the AEs from all cylinders.…”