Introduction to Perovskite Solar Panel Cells
Perovskite solar cells are a new type of solar cell made from a class of man-made materials called perovskites. Perovskites are a different material than the silicon wafers that make up traditional solar panels. They have a crystallographic structure that makes them highly effective at converting photons of light from the sun into usable electricity. Perovskite solar cells represent a high-efficiency, low-cost solar technology, and shall be the future replacement for traditional silicon solar panels.
+ Molecular Engineering of Sensitizers for Dye-Sensitized Solar Cells and Organic Light-Emitting Diodes
+ Perovskite solar cells
+ Design and development of charge transporting materials
+ Photophysics and Photochemistry of Molecular Assemblies
Perovskite Solar Cells Technology
Photovoltaics (PVs), where electricity is generated directly from sunlight, represents an ideal solution to supply sustainable, environmentally friendly, and grid-free electricity. Silicon solar cells have dominated the research and the PV market since the ’70s, leading to power conversion efficiency (PCE) of 26%. However, presently several new PV technologies are the focus of intense research, aiming for alternatives with a lower cost and higher accessibility to the general population. In 2009 a new technology, Perovskite Solar Cells (PSCs), revolutionized the PV research showing an impressive improvement on PCE from 3.8% to 23% in only 7 years, a record for a recently-developed technology, while the dominant silicon solar technology efficiency reaching 26%.2 Perovskite Solar Cells (PSC) are based on hybrid crystalline material which possess a three-dimensional (3D) crystal structure ABX3 where A is an organic cation (typically R-NH3+), B is a metal cation (typically Pb+2 or Sn+2), and X is a halide anion, forming an octahedral in the unit cell (see Fig. 2a). The hybrid perovskite materials have significant advantages for optoelectronic applications due to their combined electrical and optical properties in terms of high absorption coefficient, ambipolar charge transport properties, long carrier diffusion lengths and extremely low exciton binding energy. Additionally, the ability to tune the perovskite band gap by simple chemical substitution (i.e. by manipulation of the “A” cation and “X” halide substitution) together with their facility to be solution-processable from inexpensive precursors and simple fabrication methods, make them competitive with the existing PV materials such as silicon or Cu(InGa)Se2 (CIGS) in terms of efficiency and, more importantly, lower cost. Typical PSC exploits a sandwich n-i-p configuration where the perovskite is deposited on top of a mesoporous titanium dioxide (TiO2) or tin dioxide (SnO2) layer, which behaves as electron transport material (ETM), and covered by a hole transporting material (HTM), crucial to facilitate the extraction of holes from perovskite to the back contact. Other sandwiched structure has also been developed such as n-i-p planar or inverted (p-i-n) architecture. Both ETM and HTM and their interfaces with the perovskite are of paramount importance in governing charge collection and extraction to the contacts, and thus the overall device performances. The highest PSC efficiency in Nazeeruddin’s laboratory is at present 21.3% (see Fig. 2b) comparable to what is published so far in literature (PCE=22.1%) based on n-i-p mesoscopic architecture. These results emanate from the compositional engineering of the cations (A) and anions (X), using a nonstoichiometric lead iodide precursor and a solvent-engineering method to grow the over layer of perovskite on the mesoporous layer.
One of the most exciting parts of perovskites is their high efficiencies. Based on lab calculations, perovskite solar cells are capable of beating the capabilities of traditional mono- or poly-crystalline silicon cells. Another advantage of perovskite solar cells is that they are based on a human-made material that can be produced at a low cost. Perovskite solar cells are a new type of solar cell made from a class of man-made materials called perovskites. Perovskites are a different material than the silicon wafers that make up traditional solar panels. They have a crystallographic structure that makes them highly effective at converting photons of light from the sun into usable electricity. Perovskite solar cells represent a high-efficiency, low-cost solar technology, and shall be the future replacement for traditional silicon solar panels.
Presently, over 85% of the World’s energy requirements are satisfied by fossil fuels with devastating consequences on the environment and society.1 The energy demand is predicted to increase by almost 30% during the next 20 years due to population growth and, consequently, solar energy is considered as the ultimate source of clean, secure, and renewable electricity. The world global installed photovoltaic (PV) capacity will reach well over 1000 GW by 2030 and could reach up to 5000 GW by 2050. At this moment, solar energy will be one of the major electricity sources worldwide, with the lowest costs and environmental impact, while contributing to mitigating CO2 gas emissions. Solar energy is indeed recognized as the fastest growing technology by the World economic forum (press, October 2017), and appointed as the future solution for a carbon-free economy given the limited finite sources of planetary energy reserves (see Figure 1). The use of silicon-based solar systems is widespread accounting for over 90% of the installed PV. However, their manufacturing costs remain high due to in part technologically intensive fabrication of silicon wafer. New PV technologies with higher potential performances at a lower manufacturing and materials cost will lead to a change in thinking in energy generation. In this context, the innovative technology based on Perovskite solar cells (PSCs) has emerged in the last few years and nowadays considered one of the most excited PV technologies of our time. PSCs are leading a real revolution in power generation, standing over the main technologies on the market, reaching power conversion efficiency (PCE) surpassing 23%. In addition to high efficiency, their low-temperature solution deposition methods compatible with printing are the great advantage over existing technologies making the PSCs cost effective with the levelled cost of electricity below the mainstream silicon photovoltaics.
The groups’ focus is Molecular Engineering of Functional Materials for Photovoltaic and Light emitting applications. In the field of molecular-based photovoltaic devices, dye-sensitized solar cells (DSCs) have reached an efficiency of over 13%. This efficiency level, coupled with the use of inexpensive materials and processing has stimulated momentum to industrialize this technology. In these cells, the sensitizer, located at the junction between electron and hole transporting phases, absorbs sunlight, and injects an electron and a hole into the n- and p-type materials, respectively. The former is an inorganic n-type wide bandgap oxide semiconductor (typically TiO2 anatase) and the latter is a liquid electrolyte or p-type hole transporter. The generated free charge carriers, travel through the nanostructured oxide to be collected as current at the external contacts. The significant advantage of DSCs is that they achieve the separation of light harvesting, and charge carrier transport, thus the maximum power point is virtually independent of light level therefore useful in all climate conditions. The general losses in dye-sensitized solar cells are due to the lack of sensitizer absorption in the near IR region, and the loss-in-potential from the optical band gap to the open-circuit voltage. The goal of the group is to engineer at molecular level novel panchromatic sensitizers and functionalized hole-transporting materials to achieve power conversion efficiency over 18%.
Recently organohalide lead perovskites have revolutionised the scenario of emerging photovoltaic (PV) technologies, with recently certified efficiency of 20.1% based on a perovskite solar cell. Such high efficiency is due to panchromatic absorption (down to ca. 800 nm), high absorption coefficient (1.4*104 cm-1 at 550 nm), low exciton binding energy (25 meV in MAPbI3), large mobility (66 cm2/Vs for MAPbI3), ambipolar charge transport, and large electron and hole diffusion lengths (175 um). The group is aiming to enhance power conversion efficiency of perovskite solar cells beyond 20%, and stability using functionalized electron and hole transporting materials. Our approach unfolds in three strategies: i) Interface engineering of new electron transporting materials; ii) Design and develop molecularly engineered novel family of large band gap hole transporting materials; and iii) Optimize the perovskite deposition techniques. The perovskite solar cell technology has been already proven to be remarkably efficient and has scope to compete with the absolute best crystalline semiconductor and thin film photovoltaic systems while offering the very lowest potential cost for materials and solution processed manufacturing. The groups’ ambitious goal of reaching power conversion efficiency 23% under 100 mW cm−2 will be realized by developing novel materials.
Using solar cells to generate hydrogen, and reduction of CO2 to fuels is an environmentally friendly process that reduces greenhouse gases. Therefore, the group will explore H2 generation via water splitting using sunlight, and CO2 reduction to liquid fuels using molecularly engineered transition metal complexes. These tailored metal complexes can act as inner sphere electron transfer agent to activate CO2.
The inverse process of dye-sensitized solar cell is producing light from electricity in organic light emitting diodes (OLEDS), which is also one of the main focuses of the group. Here the goal is to engineer highly phosphorescent emitters with blue, green, and red colours for display and lighting applications.
Enoil Biotechnologies | Perovskite Solar Cells won in 2018 the gold medal in the International Exhibition of Inventions in Geneva, Switzerland.
What is the Perovskite market?
Perovskite structures will revolutionize solar cell devices and will transform the business of solar power. The business of solar power in a 25-year period has grown exponentially, transforming the technology from rarefied oddity to the world’s fastest-growing energy source. 100MW of capacity in 1992 rocket to more than 300GW in 2016. The solar-power industry invested $160bn in 2017.
A fifth of the world’s energy consumption is supplied by renewables.
The world’s renewable power capacity could supply an estimated 26% of global electricity.
55% of new renewable power installations were solar photovoltaics (PV) and these accounted for more than the combined additions of fossil fuel and nuclear in 2017.
Global trends in solar energy indicate a critical need to provide renewable and reliable energy to the world. According to an article of The Economist, 1.5 billion people, or more than a fifth of the world’s population, currently have no access to electricity, and a billion more have only an unreliable supply. Of the people without electricity, 85% live in rural areas or on the fringes of cities. The United Nations estimates that an average of $35 billion-40 billion a year needs to be invested until 2030 so everyone on the planet can cook, heat and light their homes and have the energy for productive uses such as schooling. At the current rate of investment, however, the number of “energy poor” people will barely budge, and 16% of the world’s population will still have no electricity by 2030, according to the International Energy Agency.
What is the difference with standard solar cells?
This material has several key features. First, it is completely inorganic. This is an important shift because organic components are usually not thermostable and degrade under heat. Since solar cells can get very hot in the sun, heat stability is crucial. By replacing the organic parts with inorganic materials, the researchers made the perovskite solar cells much more stable. “The solar cells are almost unchanged after exposure to light for 300 hours”.
What is a Perovskite structure?
Perovskite structures work well as the light-harvesting active layer of a solar cell because they absorb light efficiently but are much cheaper than silicon. Perovskite, is a mineral found in the earth, is composed of calcium, titanium and oxygen in a specific molecular arrangement. Materials with that same crystal structure are called perovskite structures.
Prof. Md. K. Nazeeruddin received M.Sc. and Ph. D. in inorganic chemistry from Osmania University, Hyderabad, India. He joined as a Lecturer in Deccan College of Engineering and Technology, Osmania University in 1986, and subsequently, moved to Central Salt and Marine Chemicals Research Institute, Bhavnagar, as a Research Associate. After one-year postdoctoral stay with Prof. Graetzel at Swiss federal institute of technology Lausanne (EPFL), he joined the same institute as a Senior Scientist.
In 2014, EPFL awarded him the title of Professor. His current research at EPFL focuses on Dye Sensitized Solar Cells, Perovskite Solar Cells, CO2 reduction, Hydrogen production, and Light-emitting diodes. He has published more than 509 peer-reviewed papers, ten book chapters, and he is inventor/co-inventor of over 50 patents. The high impact of his work has been recognized by invitations to speak at over 130 international conferences.
- Doctor of Philosophy (Ph.D), Inorganic Chemistry, 1986, Osmania University, Hyderabad, India.
- Master of Science (M.Sc), Inorganic Chemistry, 1980, Osmania University, Hyderabad, India. Passed with first class and distinction.
- Bachelor of Science (B.Sc), Chemistry and Biology 1978, Osmania University, Hyderabad, India. Passed with first class and distinction.
- World Class University Professor, 2009-2013, Department of Advanced Materials Chemistry, Korea University (Sejong Campus), 208 Seochang, Jochiwon, Chungnam 339-700, Korea. Contact: Tel. +82 41 860 1383, firstname.lastname@example.org
- King Abdulaziz University, Jeddah, SaudiArabia, 2014-2015
- King Saud University, SaudiArabia-P.O:2454, Riyadh11451.
- EPFL award for Excellence, 2006
- Brazilian FAPESP Fellowship Award, 1999
- Japanese Government Science & Technology Agency Fellowship, 1998
- EPFL award for Excellence, 1998
- Government of India National Scholar award, 1987-1988
- CSIR, Senior research Fellowship, 1983-1986
- CSIR, Junior research Fellowship, 1980-1983
Editorial board member:
- Artificial Photosynthesis www.versitaopen.com/arph
- ACS Applied Materials & Interfaces
- Nature Scientific Reports
From the Press
Forget silicon. This material could be a game-changer for solar power
EPFL Prize Awards
Top 5 scientists
Arts et Métiers
Enoil Biotechnologies an Advanced Biotechnology and Renewable Energy company based in Switzerland.
Rue Muzy 1
+ 41 22 548 11 00
Duchosal Berney SA
Enoil Bioenergies Italia SPA
Enoil Bioenergies Italy SPA is an Advanced Biotechnology and Renewable Energy company registered in Italy.
Via Torrenera, 6
40043 Marzabotto BO
Società di Revisione