Indoor solar - Page 4

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Solaires is recycling indoor light to power IoT and electronic devices

Solaires Entreprises Inc. is a Canadian solar energy startup based in Victoria, BC., who has developed perovskite photovoltaic (PV) modules, designed for integration into IoT devices, small consumer electronics, and smart gadgets. Powered by indoor light, the cells are extremely efficient, modular, and are configurable to suit the application.  

For years, the consumer electronics industry has dreamt of new technologies to power or recharge devices with indoor light. Perovskite modules are the most suitable solution and Solaires is proud to announce their perovskite PV modules are now available to the market for evaluation and integration into your devices! The company offers custom module sizes tailored to perfectly suit your needs. Those familiar in this space will appreciate that Solaires PV modules provide superior light absorption to traditional materials.

Why perovskite technology?

Theoretically, the best absorber materials for indoor applications should have an energy band gap between 1.8 to 2.0 eV. Silicon, with a bandgap between 1.1 to 1.6 eV shows poor performance for indoor light. Perovskite, though, has a tunable bandgap. Solaires’ team can adjust the bandgap to be between 1.2 to 2.6 eV, making perovskite PV modules suitable for generating high power from indoor light. This is achieved by a simple and cost effective solution processed to engineer the perovskite composition and the resulting band gap. As a result, Solaires can make perovskite PV modules suitable for generating high power from indoor light.

Fig. 1 illustrates the efficiency of perovskite, note the red area signalling the bandgap for electric light.

Researchers at the Research Institute of Sweden (RISE) and KTH Royal Institute of Technology have presented the ionic liquid (IL) synthesis of two novel pseudo-2D perovskite-type gold(III)polyiodide compounds and their use as active layers in monolithic solar cells.

The team stated that its recent work represents the first demonstration of film deposition of gold iodide/polyiodide compounds onto porous monolithic substrates with subsequent solar cell characterization. The devices reportedly showed promising photovoltaic performance and could unlock new materials design possibilities, ultimately moving away from lead-based photovoltaic materials. These findings further highlight the use of simple polyiodide entities to increase the structural and electronic dimensionality of gold perovskite-type anions.

Researchers at the Indian Institute of Technology Mandi, National Institute of Solar Energy (NISE) and University of North Texas have reported perovskite-based solar technology that can generate power when irradiated with light produced in household light sources like LED or CFL.

The results of this research could support IoT technology, which is being increasingly used in mobile phones, smart homes, and other applications that require various kinds of real-time data. These IoT devices are required to run independently without relying on electrical grids for power supply; primary and secondary batteries are currently used to power such devices. All batteries, irrespective of their kind, have a finite lifespan and are neither cost-effective nor eco-friendly.

Researchers at CSIRO and Monash University have reported a flexible perovskite solar cell manufactured using roll-to-roll compatible “printing” type processes, which could potentially be used in large-scale manufacturing. To achieve this, the team developed a viable roll-to-roll process to deposit the electrode layer, which has thus far been a major challenge. The team managed to fabricated cells which achieved a maximum efficiency of 16.7%.

Photo: Hasitha Weerasinghe/CSIRO

Roll-to-roll processes signify a potential for low-cost manufacturing of flexible perovskites. However, adding the electrode layer in a process compatible with the roll-to-roll setup has proven to be a challenge. The research team in this recent work set out to address this issue and develop a process that could allow the electrode layer to be deposited without the need for solvents or heat treatments that potentially damage the perovskite layer as well.

The CEA at INES has reported the design of flexible perovskite solar modules with a surface area of 11.6 cm² and a power conversion efficiency of 18.9% (stabilized efficiency > 18.5%). This performance is said to be a world record for flexible perovskite modules over 10 cm².

Perovskite-based modules before and after flexible encapsulation. Image credit: CEA

For some applications, the use of flexible substrates may be attractive for single-junction perovskite technology as it opens the way to high-speed, low-temperature printing processes. Thus, it becomes possible to use low cost substrates whereas inorganic flexible technologies, such as CIGS, require higher temperature processes and substrates that are more expensive. Many teams around the world are trying to meet the challenges of making larger area devices with sufficient stability for real-life applications. This is one of the tasks standing before partners of the European APOLO project, as part of which these results were obtained.

Saule Technologies' perovskite-based PV cells have reached 25.5% efficiency, as confirmed by laboratory measurements at the Fraunhofer ISE group of Dr. Uli Würfel.

The measurements were carried out under 1000 lux illumination by a cold white LED, which represents the real-life environment for the first commercial application of these devices.

Researchers from the University of Cambridge, Imperial College London and Soochow University in China have discovered that unique lead-free perovskite materials could be useful for indoor light harvesting. The team has found that these environmentally friendly materials could harvest enough energy from indoor light to power wireless smart devices.

A novel way to power the multitude of electronic devices we use daily is by converting indoor light from ordinary bulbs into energy, in a similar way to how solar panels harvest energy from sunlight. However, due to the different properties of the light sources, the materials used for solar panels are usually not suitable for harvesting indoor light.

MIT researchers have designed perovskite photovoltaic-powered sensors that could potentially transmit data for years before they need to be replaced. To this end, the team mounted thin-film perovskite cells as energy-harvesters on inexpensive radio-frequency identification (RFID) tags.

The cells could power the sensors in both bright sunlight and dimmer indoor conditions. Moreover, the team found the solar power actually gives the sensors a major power boost that enables greater data-transmission distances and the ability to integrate multiple sensors onto a single RFID tag.

Saule Technologies has announced that it has reached the point of technology development to be able to print its flexible, lightweight, semi-transparent, single junction solar modules with a consistent 10% efficiency. This performance, according to the Company, already enables BIPV and IoT applications in an economically viable manner.

By the end of March, Saule Technologies has also reached as high as 17.6% efficiency at the cell level (measured by an independent research institute). The durability has been significantly improved as well, with the latest stability tests indicating multiple years of flawless operation under accelerated ageing tests.

Researchers from the Research Center for New Generation Photovoltaics (RCNPV) in Taiwan have developed solid-state perovskite solar cells which can convert indoor light to power IoT sensors.

Research Center for New Generation Photovoltaics (RCNPV) director, Wu Chun-guey, said: "Power conversion for a perovskite solar cell with area of 0.0739 square cm is 23.7%, and the efficiency decreases to 20.9% for cell area of one square cm, 17.25% for 17.277 square cm, and 11.7% for 703 square cm".