On the kinetics of high intensity illuminated annealing of n-type SHJ solar cells: 0.4%abs efficiency gain in one second

Silicon heterojunction (SHJ) solar cells are at the forefront of high efficiency industrial solar cell manufacturing. The rapid increase in efficiency compared with passivated emitter and rear cell (PERC) cells has significantly propelled commercial interest in this technology. Illuminated annealing under elevated temperatures has been shown to lead to efficiency enhancements in SHJ cells. Recently, it was observed that increasing the light intensity used during the annealing can accelerate the efficiency gains, this approach has started to be incorporated into SHJ manufacturing. In this work, we investigate the kinetics of this high intensity illuminated annealing process in the temperature range from 200 °C to 300 °C, demonstrating that the kinetics and extent of the efficiency gain strongly depend on the temperature of the process. For the first time, we show that the changes in VOC and RS, which control the efficiency enhancement, occur at different rates. Remarkably, by investigating the temperature dependence we demonstrate a process that leads to efficiency gains of >0.4%abs in only 1 s. This new understanding presents a pathway to an industrially compatible annealing approach that significantly increases the power output of SHJ modules

Initiation of dendritic failure of LLZTO via sub-surface lithium deposition

The occurrence of lithium deposition in occluded spaces within ceramic electrolytes due to electronic leakage currents can jeopardise the commercialization of power-dense solid-state batteries. Here, we utilize plasma-FIB serial sectioning to visualize the surface and sub-surface of a garnet solid electrolyte (LLZTO) after lithium plating. We study the morphology of surface spallation cracks, which represent the initial stage of dendrite formation. Employing a LiMg anode, we track the magnesium diffusion around these surface cracks with EDS. The absence of magnesium in early-stage cracks suggests they form due to the pressure build-up from the deposition of pure lithium in occluded pores near the electrolyte surface. These spallation cracks act as current focusing and stress concentration hot spots. Electron beam induced current imaging demonstrates that short-circuiting lithium dendrites grow from the spallations during plating. Thus, the sub-surface deposition of lithium is a possible explanation for the initiation of lithium dendrites in LLZTO

Broadly-tunable smart glazing using an ultra-thin phase-change material

For many applications, a method for controlling the optical properties of a solid-state film over a broad wavelength range is highly desirable and could have significant commercial impact. One such application is smart glazing technology where it is necessary to harvest near-infrared solar radiation in the winter and reflect it in the summer--an impossibility for materials with fixed thermal and optical properties. Here, we experimentally demonstrate a smart window which uses a thin-film coating containing GeTe, a bi-stable, chalcogenide-based phase-change material which can modulate near-infrared absorption while maintaining neutral-colouration and constant transmission of light at visible wavelengths. We additionally demonstrate controlled down-conversion of absorbed near-infrared energy to far-infrared radiation which can be used to heat a building's interior and show that these thin-films also serve as low-emissivity coatings, reducing heat transfer between a building and its external environment throughout the year. Finally, we demonstrate fast, sub-millisecond switching using transparent electrical heaters integrated on glass substrates. These combined properties result in a smart window that is efficient, affordable, and aesthetically pleasing--three aspects which are crucial for successful adoption of green technology

Roadmap on Photovoltaic Absorber Materials for Sustainable Energy Conversion

Photovoltaics (PVs) are a critical technology for curbing growing levels of anthropogenic greenhouse gas emissions, and meeting increases in future demand for low-carbon electricity. In order to fulfil ambitions for net-zero carbon dioxide equivalent (CO2eq) emissions worldwide, the global cumulative capacity of solar PVs must increase by an order of magnitude from 0.9 TWp in 2021 to 8.5 TWp by 2050 according to the International Renewable Energy Agency, which is considered to be a highly conservative estimate. In 2020, the Henry Royce Institute brought together the UK PV community to discuss the critical technological and infrastructure challenges that need to be overcome to address the vast challenges in accelerating PV deployment. Herein, we examine the key developments in the global community, especially the progress made in the field since this earlier roadmap, bringing together experts primarily from the UK across the breadth of the photovoltaics community. The focus is both on the challenges in improving the efficiency, stability and levelized cost of electricity of current technologies for utility-scale PVs, as well as the fundamental questions in novel technologies that can have a significant impact on emerging markets, such as indoor PVs, space PVs, and agrivoltaics. We discuss challenges in advanced metrology and computational tools, as well as the growing synergies between PVs and solar fuels, and offer a perspective on the environmental sustainability of the PV industry. Through this roadmap, we emphasize promising pathways forward in both the short- and long-term, and for communities working on technologies across a range of maturity levels to learn from each other.Comment: 160 pages, 21 figure

Data for Controlling surface carrier density via a PEDOT:PSS gate: An application to the study of silicon-dielectric interface recombination

Excel sheets for Sinton photoconductance lifetime data of all samples measured in this work. Sumamry figures 1 and 2 are also included in Matlab format with embedded data

Data for Controlling surface carrier density via a PEDOT:PSS gate: An application to the study of silicon-dielectric interface recombination

Excel sheets for Sinton photoconductance lifetime data of all samples measured in this work. Sumamry figures 1 and 2 are also included in Matlab format with embedded data

Data for dielectric surface passivation for silicon solar cells: A review

Embedded Matlab raw data on effective lifetime, surface recombination velocity, implied open circuit voltage, and recombination current density for different passivation dielectrics

Data for dielectric surface passivation for silicon solar cells: A review

Embedded Matlab raw data on effective lifetime, surface recombination velocity, implied open circuit voltage, and recombination current density for different passivation dielectrics