High Efficiency Organic Solar Cells Achieved by the Simultaneous Plasmon‐Optical and Plasmon‐Electrical Effects from Plasmonic Asymmetric Modes of Gold Nanostars

Abstract

The plasmon-optical effects have been utilized to optically enhance active layer absorption in organic solar cells (OSCs). The exploited plasmonic resonances of metal nanomaterials are typically from the fundamental dipole/high-order modes with narrow spectral widths for regional OSC absorption improvement. The conventional broadband absorption enhancement (using plasmonic effects) needs linear-superposition of plasmonic resonances. In this work, through strategic incorporation of gold nanostars (Au NSs) in between hole transport layer (HTL) and active layer, the excited plasmonic asymmetric modes offer a new approach toward broadband enhancement. Remarkably, the improvement is explained by energy transfer of plasmonic asymmetric modes of Au NS. In more detail, after incorporation of Au NSs, the optical power in electron transport layer transfers to active layer for improving OSC absorption, which otherwise will become dissipation or leakage as the role of carrier transport layer is not for photon-absorption induced carrier generation. Moreover, Au NSs simultaneously deliver plasmon-electrical effects which shorten transport path length of the typically low-mobility holes and lengthen that of high-mobility electrons for better balanced carrier collection. Meanwhile, the resistance of HTL is reduced by Au NSs. Consequently, power conversion efficiency of 10.5% has been achieved through cooperatively plasmon-optical and plasmon-electrical effects of Au NSs.

Plasmonic Gold Nanostars Incorporated into High‐Efficiency Perovskite Solar Cells

“…Compared with AuNPs and AuNRs, AuNSs are unique in their structure that consists of a central core with multibranched (tips) surface . These unique nanostructures result in a well‐defined double localized surface plasmon resonance (LSPR) peaks at 495–560 nm (core) and 650–680 nm (multibranched tips) (see Figure S2 d), which are expected to lead to strong local electromagnetic field enhancement around the branched tips and also an improved light‐scattering effect .…”

“…Figure1cs hows the UV/Vis absorption spectrum of AuNSsd ispersed in water.T he appearance of the strong resonance band of AuNSs centered at al ong wavelength of > 650 nm is due to the formation of tips, whereas the shoulder at approximately 530-550 nm is associated with the transverse plasmon mode of the cores. [16] Such AuNSs are expectedt oh ave strong local electromagnetic field enhancement aroundt he pods/tips anda lso provide excellent light scattering, [16,17] which will lead to an enhancement in LHE of the devices.T ov erify the presence of the AuNSs in the meso-porousT iO 2 ,t he photoelectrodes were characterizedu sing X-ray photoelectrons pectroscopy (XPS). Figure S1 in the Supporting Information shows the Ti 2p (a) and Au 4f spectra (b).…”

“…[11][12][13][14][15]18] Compared with AuNPs and AuNRs, AuNSs are unique in their structure that consists of ac entral core with multibranched (tips) surface. [17] These unique nanostructuresr esult in aw ell-defined double localized surface plasmon resonance (LSPR) peaks at 495-560 nm (core) and 650-680 nm (multibranched tips) (see FigureS2d), which are expected to lead to strong local electromagnetic field enhancement around the branched tips and also an improved light-scattering effect. [16] Therefore, the improved efficiency for structures using AuNSs in comparison to the other nanoparticles can be attributed to ab etter overlap between the LSPR excitation wavelengths in collaboration with the mixed perovskite absorber combined with localized field enhancementd ue to the jagged structures.…”

Improving the performance of inverted organic solar cells by embedding silica‐coated silver nanoparticles deposited by electron‐beam evaporation

“…It is known that embedding MNPs inside the OSC devices can improve the electrical properties; this has been demonstrated through a spatially redistributed light absorption in the active layer. Sha et al reported that plasmonic effects play a key role in the enhancement of the total exciton generation and the dense exciton generation around plasmonic nanostructures providing an effective way to improve both the electrical and optical properties of OSCs …”

Effect of Au nanoparticles on PCPDTBT:PC 71 BM device performance with fair comparisons

“…Consequently, a relatively clear coincidence between IPCE and extinction behavior was observed, implying that the near field effect is supposed to be a dominant path for the enhanced device performance. The current devices have shown a lower PCE, however, the device performance remains a topic for future studies such as of electrical properties, proper plasmonic structures and so on .…”