Indoor solar - Page 3

Researchers at the Indian Institute of Technology Mandi (IIT-Mandi), the National Institute of Solar Energy (NISE) and China's Guangxi University have designed efficient indoor bifacial perovskite photovoltaics (i-BPPVs) with the capability of harvesting maximum light from both top and bottom sides. This achievement could be a significant step towards advancing cost-effective and efficient technology for harvesting more energy from artificial indoor light sources.

The i-BPPVs were designed and fabricated in a stack of organic–inorganic hybrid perovskite material amid a transparent bottom electrode (ITO), and top (Au/ITO) electrode. The fabricated i-BPPVs exhibited an efficiency of 30.3%, short circuit current density (JSC) of 148.3 µA cm⁻², open circuit voltage (VOC) of 0.93 V, and fill factor (FF) of 71.7% when artificial LED light source of 1000 lx is exposed from the top side, whereas an efficiency of 22.1%, JSC of 116.2 µA cm⁻², VOC of 0.89 V, and FF of 69.4% have been obtained from the bottom side. 

Australia-based Greatcell Solar Materials produces and supplies perovskite materials, and is one of the industry's pioneer companies. We conducted an interviw with Dr. Yanek Hebting, Greatcell's general manager, who updates us on the company's business, material and his views on the perovskite industry.

Hello Dr. Hebting, Thank you for this Q&A. Can you introduce us to Greatcell Solar Materials?

Greatcell Solar Materials Pty Ltd was created in October 2018 as the spin-off of the Materials Division of Greatcell Solar, formerly Dyesol. Greatcell Solar Materials is a manufacturer and supplier of materials (including perovskite precursors, dyes, ligands, titania pastes, electrolytes as well as components) for energy system applications to the photovoltaics research sector and the electronics industry.

All products are manufactured and shipped from our facility in Queanbeyan, NSW Australia.

Can you tell us a bit about the demand for perovskite materials? Does it come mostly for research, or pilot lines?

As COVID restrictions around the world have eased and global activity resumed, the demand for perovskite materials has significantly increased since.
Greatcell Solar Materials provides both bulk quantities for industrial partners as well as small quantities for research purposes. The demand for research purpose will always be a part of the demand, it is exciting to see some pilot lines take fruition and begin the process of commercialization.

Researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) and the University of Toledo have found that perovskite solar cells should be subjected to a combination of stress tests simultaneously to best predict how they will function outdoors.

The team used a state-of-the-art p-i-n PSC stack (with PCE up to ~25.5%) to show that indoor accelerated stability tests can predict 6-month outdoor aging tests. Device degradation rates under illumination and at elevated temperatures are most instructive for understanding outdoor device reliability. The team also found that the indium tin oxide (ITO)/self-assembled monolayer (SAM)-based hole transport layer (HTL)/perovskite interface most strongly affects the device operation stability. Improving the ion-blocking properties of the SAM HTL increases averaged device operational stability at 50°C–85°C by a factor of ~2.8, reaching over 1000 h at 85°C and to near 8200 h at 50°C with a projected 20% degradation, which is among the best to date for high-efficiency p-i-n PSCs.

Graphitic materials supplier First Graphene has announced an R&D collaboration with Greatcell Energy, trading as Halocell Energy, and the Queensland University of Technology (QUT) to commercialize perovskite solar cell fabrication. The project has received a Cooperative Research Centers Project (CRC-P) grant worth over AUD$2 million (around $USD1,300,000).

The research and development project is intended to commercialize ultra-low-cost, flexible perovskite solar cell fabrication using Halocell’s roll-to-roll production process at the company’s Wagga Wagga plant, First Graphene said in an announcement. Through the project, First Graphene plans to develop cost-effective graphene-based electrode replacements for high-cost conductor materials, such as gold and silver, used in cell manufacturing.

Japanese electronics giant, Toshiba, has reportedly achieved a power conversion of 16.6% for a 703cm² polymer film-based perovskite solar module.

Toshiba representatives were quoted saying that the Company has provided large film-based perovskite PV module as experimental materials for demonstrations, probably referring to a project conducted at the Aobadai station in Yokohama that includes analyzing indoor performance.

Solaires Entreprises Inc. is a Canadian solar energy startup based in Victoria, BC., who has developed perovskite materials and 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.

Dr. Sahar Sam is Solaires Chief Science Officer, and she was kind enough to answer a few questions we had about Soliares. Dr. Sam holds a B.Sc. and an M.Sc. in Materials Science and Engineering from Shiraz University and a Ph.D. in Mechanical Engineering from the University of Victoria. 

Hello Dr. Sam! We'll be happy to get a short introduction to Solaires, the technology, and products.

Founded in 2020 in Victoria, BC, Solaires Entreprises Inc is at the forefront of the next generation of photovoltaics, targeted for both outdoor light and indoor light, by harnessing the promise of perovskites. Our perovskite photovoltaics are light, thin and made of readily available and low cost materials.

A collaborative effort by researchers from the Centre for Hybrid and Organic Solar Energy (CHOSE), Department of Electronic Engineering at Tor Vergata University of Rome, Italy, the Department of Textile Engineering at the University of Guilan, Iran, GreatCell Solar Italia, Institute of Crystallography (IC-CNR), Italy, Department of Biological and Environmental Sciences and Technologies at the University of Salento, Italy and Institute of Nanotechnology (CNR NANOTEC), Italy, has resulted in the development of flexible perovskite solar cells with remarkable power conversion efficiencies (PCE) under white LED illumination.

The team achieved a maximum PCE of 28.9% at an illuminance of 200 lx and a record of 32.5% at 1000 lx, essentially converting a third of the incoming power (note that under 1 sun this figure for perovskite technology is less, i.e. one quarter).

Researchers from Stanford University and Mississippi State University recently explored the potential of Mn²⁺-doped perovskite LEDs (PeLEDs) for lighting and display applications. 

By introducing a molecular additive, tris(4-fluorphenyl)phosphine oxide (TFPPO), Mn²⁺-doped PeLEDs achieved a peak external quantum efficiency of 14.0% and peak luminance (i.e., brightness) of 128,000 cd/m². These high efficiencies and brightnesses suggest that Mn²⁺-doped PeLEDs could be implemented in lighting or display applications. However, device stability is also important to consider. The team found that introducing TFPPO compromises the stability of Mn²⁺-doped PeLEDs—a decrease from 37.0 to 2.54 min. By analyzing both the optoelectronic and photophysical characteristics of Mn²⁺-doped PeLEDs before and after device operation, the scientists reported insights into this efficiency-stability trade-off.

Sweat is less invasive to collect than blood, and can tell a lot about a person's health. This is the premise behind the wearable sweat sensors developed by Wei Gao, assistant professor of medical engineering at the California Institute of Technology (Caltech). Over the past five years, Gao has steadily added features to his wearables, making them capable of reading out levels of salts, sugars, uric acid, amino acids, and vitamins as well as more complex molecules like C-reactive protein that can provide timely assessment of certain health risks. Most recently, in collaboration with Martin Kaltenbrunner's group at Johannes Kepler University Linz in Austria, Gao has powered these wearable biosensors with a flexible perovskite solar cell (FPSC).

Perovskite is as much as 1,000 times thinner than silicon solar cell layers, making them "quasi-2D" in Gao's terms. Perovskites can also be tuned to the spectra of different lighting, from outdoor sunlight to various forms of indoor lighting. Importantly, perovskite solar cells can achieve a higher power conversion efficiency (PCE) than silicon, which means they can convert a greater proportion of the light they receive into usable electricity. The flexible perovskite solar cell (FPSC) on Gao's wearable sweat sensor has a record-breaking PCE exceeding 31 percent under indoor light illumination. 

Researchers from Thailand's Mahidol University, Chiang Mai University, the Center of Excellence for Innovation in Chemistry (PERCH-CIC) and the National Metal and Materials Technology Center (MTEC) have developed triple-cation perovskite solar cells for low-light applications using a manufacturing process based on antisolvent deposition and vacuum thermal annealing (VTA).

“VTA leads to compact, dense, and hard morphology while suppressing trap states at surfaces and grain boundaries, which are key culprits for exciton losses,” the team stated, emphasizing the importance of the second step to produce a high quality perovskite layer. “As indoor light intensity is at least 300 times lower than that of sunlight, dense and homogeneous perovskite formation enticed by vacuum thermal annealing is valuable.”