Can computational approaches aid in untangling the inherent complexity of practical organic photovoltaic systems?

Abstract

Organic materials, in particular conjugated polymers, have recently become the subject of extensive research for photovoltaic device applications. This increase of interest is primarily the result of their potentially low manufacturing cost, compatibility with flexible substrates, diverse chemical tunability, scalability, and ease of processing currently available for suitable bulk heterojunction (BHJ) construction. However, to date, these materials have not been able to exceed power conversion efficiencies (PCE) beyond 5-9%, values short of those considered commercially viable. The deficit in PCE appears to derive from a combination of physicochemical and device complexities associated with inadequate hole transport mobility, solubility and miscibility with an appropriate acceptor, narrow electronic band gap for efficient solar light harvesting, appropriate highest occupied molecular orbital (HOMO) and lowest unoccopied molecular orbital (LUMO) energies to maximize the open-circuit voltage (V oc ) and electron transfer to the acceptor, and in particular the control of the multidimensional problem of BHJ morphology. In this review article, we provide an overview of some of the recent progress toward implementing theory, modeling, and simulation approaches in combination with results from precision synthesis, characterization, and device fabrication as a mean to overcome/understand the inherent issues that limit practical applications of organic photovoltaics.

Structure and optoelectronic properties of helical pyridine–furan, pyridine–pyrrole and pyridine–thiophene oligomers

“…In spite of impressive developments, these devices are still not comparable to inorganic devices in terms of stability and efficiency. [1][2][3][12][13][14] Thus, discovery of newer materials and studying their suitability in terms of stability followed by designing and engineering of devices are crucial for further development. In this scenario, theoretical investigations substantially assist the research and development in this field by improving the understanding of structural aspects and optoelectronic properties of new organic molecules at a molecular level and their effects on the performance of new devices.…”

New insights into the dynamics and morphology of P3HT:PCBM active layers in bulk heterojunctions

“…In order to find ways to overcome these limitations, computational approaches have been utilized for deciphering the roles of different variables that could improve the PCE and lifetime of an OPV cell. 9 A number of such studies have focused [10][11][12][13][14][15][16] on some or all of the pertinent steps in solar energy conversion in an OPV device. These steps in chronological order are: (1) the absorption of light and exciton (i.e., electron-hole pair) generation; (2) the diffusion of the exciton to an interface; (3) the separation of the exciton into an electron and a hole; (4) the transport of these electrons and holes to their corresponding electrode; and (5) the transfer of electrons and holes from the electrode to an external circuit.…”

Molecular design and performance improvement in organic solar cells guided by high‐throughput screening and machine learning

“…In order to approach to the theoretical limit of OSCs, strenuous research efforts had been made in these three aspects: (1) design and synthesize novel donor and acceptor materials, (2) optimize fabrication conditions and device structures, and (3) explore the mechanism of device operation. [ 10 ] The first two methods are a trial‐and‐error procedure, which requires expensive materials, long‐time consumption, and large manpower input while the last manner is a new way to study the physicochemical properties of materials and to simulate the device operation processes only based on multiscale computational methods, such as Density Function Theory (DFT), Molecular Dynamics (MD), Monte Carlo (MC) and so on, [ 11–17 ] which provides helpful guidelines and insight for designing novel molecules. In principles, the final device performance is only dependent on its materials and the function of manufacturing technology and device structures is to better give play to the role of materials.…”