Broadband Absorption and Efficient Hot-Carrier Photovoltaic Conversion based on Sunlight-induced Non-radiative Decay of Propagating Surface Plasmon Polaritons

Abstract

Localized surface plasmon polaritons (SPPs), which can decay non-radiatively into hot carriers, have been widely employed to extend the responses of traditional semiconductor-based photocatalytic and photovoltaic devices to sub-bandgap photons. However, radiative decay is unavoidable and adverse to device performances. Here, we propose to take advantage of propagating SPPs, another form of SPPs, which possess non-radiative decay only. A special gold-titanium dioxide nanowire array with each nanowire capped with a nanocone is proposed. The adjacent nanocones forming top gradual openings attribute to efficient sunlight harvesting, while the neighbouring nanowires forming bottom nanoslots allow sufficient absorption due to the propagating SPPs. With the combined advantages, almost 100% of light is absorbed by a very thin gold film in the visible range, and 73% in the whole considered range of 400–1170 nm, superior to the nanocone cell based on localized SPPs, let alone the nanowire-based and planar counterparts. Therefore, much better photovoltaic conversion performance is achieved with short-circuit current density of 0.74 mA/cm2 and open-circuit voltage of 0.41 V. This work confirms the superiority of non-radiative decay of propagating SPPs to the localized SPPs in terms of generation of hot carriers, providing a promising way of extracting electrons in metal into photocurrent.

Hot-carrier optoelectronic devices based on semiconductor nanowires

“…PLEASE CITE THIS ARTICLE AS DOI: 10.1063/5.0038263 using plasmonic metal elements on thin semiconductor films. Motivated by the large surface area on which the plasmonic particles can be deposited, nanowires have also been studied in this context.Hotcarrier injection from plasmonic gold particles on a nanowire surface, via Schottky contacts to nanowires of ZnO, 139 TiO2, 140 and Cu2O 24 has been observed. Regarding the efficiency of the photoemission process, White and Catchpole 141 note that since excitation in the metal can happen to a large extent well below the Fermi level, only a portion of excitations will result in carriers to be photo-emitted over the barrier.…”

“…[145][146][147][148] The high aspect ratio of nanowires makes them very suitable for the implementation of plasmonic elements that can be used to control absorption 149 or inject hot carriers. 24,139,140 Additionally, ordered arrays of nanowires have been demonstrated to possess a very low refractive index and significantly higher absorption than bulk or thin-film counterparts, mainly due to light scattering and trapping in and between the nanowires (Section V.D). [150][151][152] • The high surface/volume ratio restricts the phase space for scattering, potentially affecting hotcarrier relaxation and phonon decay dynamics.…”

Instantaneous Property Prediction and Inverse Design of Plasmonic Nanostructures Using Machine Learning: Current Applications and Future Directions

“…Plasmonic metamaterials enable the achievement of near-zero and negative refractive index, which enables the design of superlenses that circumvent the diffraction limit of light as well as cloaking devices and control over spontaneous emission through the Purcell effect [20][21][22][23]. The non-radiative dephasing of plasmons results in the formation of hot electron-hole pairs, which in turn, have been used to enhance the performance of photocatalysts, photovoltaics and photodetectors (Figure 1c) [24][25][26][27][28][29].…”

Ultra-High-Responsivity Vertical Nanowire-based Phototransistor under Standing-Wave Plasmon Mode Interaction Induced by Near-Field Circular OLED

“…The strong excited-electron field improves the excitation rate of the plasmon polaritons, and increases the radiative decay rate of photons close to the electrode nanostructures, leading to weaker resonance in the NW. 44,45 When the extrinsic light is irradiated, the plasmon coupling between the photons and ZnO NWs induces the increment of the radiative decay rate of the photon. 44−46 The work function of the ZnO NW is lower than that of Au, so the electrons in the NW are more likely to flow into the Au to balance their Fermi level.…”

“…According to LSPP theory, when the OLED is closer to the metal nanostructures, the excited-electron field gets stronger. The strong excited-electron field improves the excitation rate of the plasmon polaritons, and increases the radiative decay rate of photons close to the electrode nanostructures, leading to weaker resonance in the NW. , When the extrinsic light is irradiated, the plasmon coupling between the photons and ZnO NWs induces the increment of the radiative decay rate of the photon. − The work function of the ZnO NW is lower than that of Au, so the electrons in the NW are more likely to flow into the Au to balance their Fermi level. As a result, when the OLED is closer to the Au electrode, most of the electrons are generated in the section of the NW that is sandwiched by the OLED, resulting in a weaker resonant peak in the NW.…”