MULTI-PHYSICAL PROPERTIES OF PLASMONIC ORGANIC SOLAR CELLS (Invited Paper)

Abstract

Abstract-Organic solar cells (OSCs) have recently attracted considerable research interest. For typical OSCs, it is highly desirable to have optically thick and physically thin thickness for strong light absorption and efficient carrier collection respectively. In the meantime, most organic semiconductors have short exciton diffusion length and low carrier mobility [1][2][3]. As a consequence, the active layers of OSCs are generally thin with a thickness of a few hundred nanometers to ensure the efficient extraction of carriers, hence limiting the total absorption of incident light. Optimizing both the optical and electrical (i.e., multi-physical) properties of OSCs is in demands for rationally designed device architectures. Plasmonic nanomaterials (e.g., metallic nanoparticles [4-6], nanorods [7,8], nanoprisms [9, 10], etc.) have recently been introduced into different layers of multilayered solar cells to achieve highly efficient light harvesting. The multilayered solar cells structures commonly have active layer, carrier (electron and hole) transport layer and electrode (anode and cathode). Through the localized plasmonic resonances (LPRs) [11][12][13][14][15][16] from metallic nanomaterials, very strong near-fields will be generated, which can provide a large potential for enhancing optical absorption in the multilayered OSCs. Besides the optical effects, it has been reported that metallic nanomaterials can modify the morphology, interface properties as well as the electrical properties of OSCs which will significantly modify the performances of OSCs [17][18][19][20][21][22][23]. In this article, the effects of various optical resonance mechanisms and the theoretical studies of the multiphysical properties of OSCs will be reviewed. Meanwhile, the experimental optical and electrical effects of metallic nanomaterials incorporated in different layers of OSCs will be studied. The morphology and interface effects of metallic nanomaterials in the carrier transport layers on the performances of OSCs will also be described.

Organic Optoelectronic Materials: Mechanisms and Applications

“…Experimentally, one strategy has been to utilize surface plasmon resonance to enhance light trapping by embedding metal nanoparticles in active layers 1192−1195 or in the interlayers, 1196−1199 by utilizing nanostructured metal electrodes, 1200,1201 or both. 1202−1204 Depending on the geometry of metal nanostructure incorporation in the device, the enhanced light trapping occurs via enhanced light scattering, localized surface plasmon resonance, or surface plasmon polariton, 1191 which increases J sc .…”

“…This work also proposed a new figure of merit describing light trapping, ⟨1/ l ⟩ –1 (where l is the optical path length and the brackets designate averaging over all path lengths), and a scheme for deterministic light trapping that outperforms the Lambertian one. Experimentally, one strategy has been to utilize surface plasmon resonance to enhance light trapping by embedding metal nanoparticles in active layers − or in the interlayers, − by utilizing nanostructured metal electrodes, , or both. − Depending on the geometry of metal nanostructure incorporation in the device, the enhanced light trapping occurs via enhanced light scattering, localized surface plasmon resonance, or surface plasmon polariton, which increases J sc .…”

“…Another way of improving the PCE via device architecture is to employ various optical effects, which enhance light absorption. , A theoretical description of light management in OPVs that explicitly addresses inefficient light trapping, parasitic absorption, and nonradiative recombination losses is given in ref . This work also proposed a new figure of merit describing light trapping, ⟨1/ l ⟩ –1 (where l is the optical path length and the brackets designate averaging over all path lengths), and a scheme for deterministic light trapping that outperforms the Lambertian one.…”

Silver–copper nanoalloys-an efficient sensitizer for metal-cluster-sensitized solar cells delivering stable current and high open circuit voltage

“…From practical viewpoints, several strategies have been proposed and put forwarded to incorporate metal NPs into solar cells for their performance enhancement. In this respect, one strategy to enhance the performance of solar cells is the use of plasmonic metal NPs for improving light absorption through surface plasmon excitation phenomena [2,3]. Increasing the optical path length of light through scattering process from the plasmonic NPs has been considered another effective approach to improve the absorption in solar cells [4].…”

Dual plasmonic-enhanced bulk-heterojunction solar cell incorporating gold nanoparticles into solution-processed anode buffer layer and active layer

“…Furthermore, the electric field distributions around the Au NPs are significantly enhanced in both x and z directions, inducing an enhancement of light absorption of the active layer. Besides the light absorption enhancement, changes in the electrical properties directly induced by the LSPR effect in semiconductor–metal composite interface layer and metal oxide based carrier transport layer can enhance the carrier extraction in OSCs to get a higher device performance . Furthermore, individual Au nanoparticles can act as hole conductors because their work function is well matched with the energy of the highest occupied molecular orbital (HOMO) of P3HT , therefore, the 5 nm Au NPs acts as hole conductor to enhance the hole transport rate in the active layer .…”