Perovskite ✖ Philip Glass

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01 Introduction – How Solar Panels Works

太阳能板

When you dig deep into the mechanism of solar panels, you may find it to be photoemission effect. When light beam hits the substance, it transfers energy to all particles within. It is known to all that atoms are comprised of nucleons (protons and neutrons) and surrounding electrons. The nucleons are so tightly bonded that energy given by normal sunlight isn’t capable of overcoming the inter-particle forces. Electrons are different, they are much further away from nucleus and the attraction is relatively weak. Energy given is likely to result in a jump in energy level of electrons. 

electron emission

In the most extreme case, electrons may jump away from the attraction of nucleus and become free electrons. This process is called photoemission and the corresponding energy is called ionization energy.

Every element has its specific yet unique ionization energy and the magnitude of that determines its advantage of being the material inside solar panels. Lower ionization energy means more electrons emitted through energy transmission of light, which indicates greater solar energy – electrical energy transmission efficiency.

02 Why Perovskite?

Why is perovskite commonly chosen as a solar-cell material? The answer lies primarily in its unique crystal structure. Perovskites have the general chemical formula ABX₃, where A is a large cation, B is a smaller metal cation (commonly lead or tin), and X is a halide ion. These ions arrange themselves into a three-dimensional network of corner-sharing BX₆ octahedra, with the A-site cations occupying the spaces between them. 

Perovskite structure indication

This highly ordered yet chemically flexible structure gives perovskites exceptional electronic properties.

The arrangement of the atoms creates an electronic band structure with a band gap close to the ideal value for harvesting sunlight, typically around 1.5 eV. Since the A, B, and X ions can be substituted with different elements, the crystal structure can be engineered to precisely tune the band gap for maximum solar absorption. The overlapping orbitals within the corner-sharing octahedral framework also enable electrons and holes to move efficiently through the crystal, resulting in high charge-carrier mobility and long carrier diffusion lengths. Furthermore, the perovskite lattice is remarkably defect tolerant. Many crystal defects introduce only shallow energy levels rather than deep trap states, so electrons and holes are much less likely to recombine before reaching the electrodes. The direct band-gap nature of most halide perovskites also gives them extremely high optical absorption coefficients, allowing films only a few hundred nanometers thick to absorb most incident sunlight. 

Perovskite crystal lattice

Together, these structural characteristics make perovskites highly efficient light-harvesting materials while remaining compatible with low-temperature, solution-based fabrication methods, contributing to the rapid rise of perovskite solar cells to power conversion efficiencies exceeding 26%.

02 From Ore to Solar Panels

Perovskite materials used in solar cells are not extracted directly from natural ores but are synthesized from purified chemical precursors derived from mined elements. Lead is first extracted from ores such as galena (PbS) and refined to high purity, while iodine is obtained from brines or iodine-rich minerals and purified. These elements are then converted into compounds such as lead iodide (PbI₂) and methylammonium iodide (CH₃NH₃I), which are dissolved in a suitable solvent to form a precursor solution. This solution is deposited onto a conductive substrate by techniques such as spin coating or slot-die coating, followed by low-temperature annealing (typically 100–150 °C). During annealing, the solvent evaporates and the precursor compounds self-assemble into the characteristic ABX₃ perovskite crystal structure, producing a uniform semiconductor film that serves as the light-absorbing layer in the completed solar cell.

I would like to recommend Philip Glass's Orbit for solo cello.

 Philip Glass – Epilogue for Solo Violin

2:05

It reflects perovskite through its evolving minimalist patterns, symbolizing the material's ordered crystal structure and tunable properties. Its luminous, forward-moving character evokes efficient light harvesting and technological innovation, while its underlying delicacy mirrors the stability challenges that accompany perovskite's remarkable potential.