The conversion of sunlight into electricity by photovoltaics is currently a mature science and the foundation of a lucrative industry. In conventional excitonic solar cells, electron-hole pairs are generated by light absorption in a semiconductor and separated by the "built in" potential resulting from charge transfer accompanying Fermi-level equalization either at a p-n or a Schottky junction, followed by carrier collection at appropriate electrodes. Here we report a stable, wholly plasmonic photovoltaic device in which photon absorption and carrier generation take place exclusively in the plasmonic metal. The field established at a metal-semiconductor Schottky junction separates charges. The negative carriers are high-energy (hot) electrons produced immediately following the plasmon's dephasing. Some of the carriers are energetic enough to clear the Schottky barrier or quantum mechanically tunnel through it, thereby producing the output photocurrent. Short circuit photocurrent densities in the range 70-120 μA cm(-2) were obtained for simulated one-sun AM1.5 illumination with devices based on arrays of parallel gold nanorods, conformally coated with 10 nm TiO2 films and fashioned with a Ti metal collector. For the device with short circuit currents of 120 μA cm(-2), the internal quantum efficiency is ∼2.75%, and its wavelength response tracks the absorption spectrum of the transverse plasmon of the gold nanorods indicating that the absorbed photon-to-electron conversion process resulted exclusively in the Au, with the TiO2 playing a negligible role in charge carrier production. Devices fabricated with 50 nm TiO2 layers had open-circuit voltages as high as 210 mV, short circuit current densities of 26 μA cm(-2), and a fill factor of 0.3. For these devices, the TiO2 contributed a very small but measurable fraction of the charge carriers.

EXPERIMENTAL DETAILSSynthesis of bmp-TiN/C: Melamine (3.96 mmol) dissolved in 20 ml DMSO was mixed with equimolar TCA (3.96 mmol) dissolved in 10 ml DMSO. MTCA microfibers were obtained by adding 30 ml H 2 O into the above solution. The mixture was filtered, washed with H 2 O and dried at 90 °C. Before the infiltration of titanium precursor, the MTCA crystal was pre-heated at 350 °C. The preheated MTCA (0.3 g) was infiltrated with a titanium tetrachloride (0.1 g) solution in ethanol (6 g) and dried at room temperature for overnight. bmp-TiN/C as a black powder was finally obtained after heating at 800 °C for 3 h with a heating rate of 5 °C min -1 under nitrogen.Characterization: SEM/TEM images were taken with Hitachi S4800 and JEOL FB-2100F (HR) at an acceleration voltage of 200 kV, respectively. Powder X-ray diffraction was carried out in reflection mode (Cu Kα radiation) on a Scintag X2 θ-θ diffractometer. Nitrogen sorption analysis was conducted at -196 °C using a Micromeritics ASAP 2020. FT-IR spectra were collected on a JASCO FT-IR 470 plus with the average of 12 scans with a resolution of 4 cm -1 from 4000 cm -1 to 600 cm -1 . XPS spectra were provided by ESCALAB250. Electrochemical analysisAir cathode preparation: bmp-TiN/C, conductive carbon black (Super P, Timcal), and polyvinylidene fluoride (PVDF) polymer binder (2:6:2) were stirred in cyclopentanone for 3 hr. The dispersions of the reference Super P, Pt/C (ETEK, 20wt% Pt), and bmp-TiN/C alone were prepared with PVDF (8:2). The resulting dispersion was cast on carbon paper (AvCarb P75T) as a gas diffusion layer (GDL) and dried at 120 °C for overnight in order to remove the residual cyclopentanone or moisture. The carbon loading amount per GDL is 0.9 mg±0.2 mg. Electrolyte Preparation: TEGDME (Sigma) was distilled over a packed bed column and dried for several days over freshly activated molecular sieves (type 4Å). Battery grade lithium triflate (Sigma, CF 3 SO 3 Li, 99.995%) was used without further purification. A CF 3 SO 3 Li solution in TEGDME (molar ratio of 1:4) was prepared as an electrolyte at least one day before use.

DSSCs using g-CN as an electrocatalyst exhibit photovoltaic efficiency comparable to that of conventional Pt catalyst.

Plasmonic nanosystems have recently been shown to be capable of functioning as photovoltaics and of carrying out redox photochemistry, purportedly using the energetic electrons and holes created following plasmonic decay as charge carriers. Although such devices currently have low efficiency, they already manifest a number of favorable characteristics, such as their tunability over the entire solar spectrum and a remarkable resistance to photocorrosion. Here, we report a plasmonic photovoltaic using a 25 μm thick electrolytic liquid junction which supports the iodide/triiodide (I-/I3-) redox couple. The device produces photocurrent densities in excess of 40 μA cm(-2), an open circuit voltage (Voc) of ∼0.24 V and a fill factor of ∼0.5 using AM 1.5 G solar radiation at 100 mW cm(-2). The photocurrent and the power conversion efficiency are primarily limited by the low light absorption in the 2-D gold nanoparticle arrays. The use of a liquid junction greatly reduces dielectric breakdown in the oxide layers utilized, which must be very thin for optimal performance, leading to a great improvement in the long-term stability of the cell's performance.

A plasmonic liquid junction photovoltaic cell with greatly improved power conversion efficiency is described. When illuminated with simulated sunlight, the device (Au-TiO/V(0.018 M), V(0.182 M)/Pt) reproducibly and sustainably produces an V of 0.50 V and a J of 0.5 mA cm, corresponding to a power conversion efficiency of 0.095%.