•Incorporation of Al NPs enhanced UV–visible-NIR photovoltaic responses.•Effects of both absorption and scattering by SPs improved solar cell performance.•Chemical and field-effect passivations by SiO2 were utilized.We report to apply Al nanoparticles (NPs) to enhance the photovoltaic response of crystalline- or c-Si solar cell from the ultraviolet (UV) throughout the visible and near infrared (NIR) regimes. Al NPs were induced by solid thermal annealing and embedded in a SiO2 layer that was to passivate the front side of solar cell. Upon the excitation of surface plasmons (SPs) on the Al NPs under light illumination, an enhancement of broadband absorption of the solar cell was observed. The incorporation of Al NPs led to a relative 13.8% increase in photoelectric conversion efficiency of c-Si solar cell, and an external quantum efficiency enhancement from the UV throughout the visible and NIR regimes. The improvement of c-Si solar cell performance was attributed to both effects of absorption and scattering by SPs.Download high-res image (247KB)Download full-size image

•Surface texture and field-effect passivation are effective to improve Si solar cell performance.•A synergetic effect of surface texture and field-effect passivations is demonstrated.•The synergetic effect is facilely applicable for practical use.P-type Si substrate based solar cells were prepared with indium-tin-oxide thin films as the front top electrodes and Al layers as the rear ones. A synergetic effect of surface texture and field-effect passivations on improving Si solar cell performance was investigated. The surface texture was conducted by NaOH etching of Si, and field-effect passivations were performed by introducing SiO2 and Al2O3 thin film layers at the front and rear sides of the Si solar cell, respectively. The surface texture treatment makes the Si solar cell efficiency increase from 9.81% to 11.08%. After the synergetic treatments of surface texture and field-effect passivations, the efficiency further increased to 15.04%, that is, a more than 50% relative efficiency enhancement was obtained. This work demonstrates the significant effectiveness and facile applicability of the synergetic effect of surface texture and field-effect passivations on improving Si solar cell performance.

•A modified chemical etching approach to mass produce Si quantum dots is developed.•The Si quantum dots acquired are well dispersive and uniform in size.•Application of the Si quantum dots to commercial c-Si solar cell achieves a high relative efficiency enhancement of solar cell (3.93%).An approach to mass producing Si quantum dots (QDs) based on a controlled chemical etching process is developed. Si ultrafine powders in methanol are oxidized and etched consecutively, followed by sequential filtering. Si QDs thus obtained are well dispersive and uniform in size, and are applied to improving commercial c-Si solar cell performance by depositing Si QD-contained SiO2 sol–gel on the front surface of solar cell. A maximal relative efficiency enhancement of 3.93% is achieved after Si QD concentration optimization, and the photoelectric conversion efficiency increases from 18.05% to 18.76% via photoluminescence conversion of Si QDs.

•A facile method of producing Ag clusters on SiO2 with ultrasonic and thermal treatments is developed.•This method is readily controllable in Ag cluster size and density and applicable.•Localized surface plasmons generated on the Ag clusters enhance the photoluminescence of Si nanocrystals by a factor of 3.6.Quartz substrates are ultrasonically irradiated within AgNO3 solution, followed by postannealing in nitrogen atmosphere at elevated temperatures (Ta׳s) between 200 and 800 °C. Ag clusters with sizes in the order of 102 nm appear on the SiO2 surfaces after the ultrasonic and thermal treatments. Absorption spectra induced by localized surface plasmons (LSPs) on Ag clusters are observed. The most prominent absorption occurs for Ta=400 °C. From Ta=200 to 400 °C, AgNO3 on SiO2 experiences thermal decomposition, Ag cluster formation and ripening. From Ta=600 to 800 °C, Ag oxide nano-rings form. Application of the LSPs to Si nanocrystal-doped SiO2 (Si-NC:SiO2) thin film yields an enhancement of photoluminescence (PL) of Si-NCs, with a maximal 3.6-fold enhancement obtained for Ta=400 °C. The PL enhancement is attributed to the LSP field coupling to the exciton dipole moment of Si-NC.Ag clusters are readily formed on SiO2 via ultrasonic and thermal treatments, on which, photo-induced surface plasmons enhance the photoluminescence of Si nanocrystals inside SiO2.

A multilayered thin film of SiO/Si has been irradiated by CO2 laser in a dot by dot scanning mode, followed by furnace thermal annealing at 1100 °C to form Si nanocrystals (Si-NCs) via a phase separation process. Such a laser pre-annealing treatment could enhance the intensities of photoluminescence and electroluminescence of Si-NC by a factor of ∼3 for both. Characterization measurements show that the enhancements are due to the production of extra nucleation sites for Si-NCs, which suppresses the formation of large sized and poorly luminescent Si particles and increases the density of highly luminescent Si-NC.Highlights► To develop a novel methodology of laser preannealing to enhance the light emission of Si (both PL and EL). ► The laser preannealing in a dot by dot scanning mode introduces extra nucleation sites, hence the formation of large size and poorly luminescent Si particle is suppressed, and that of Si nanocrystal is facilitated. ► This laser preannealing treatment is different from usual RTA (rapid thermal annealing) one that induces Si nanocrystal formation directly, where laser irradiation covers the whole sample for a short time.