Reagents for Organic-Inorganic Perovskite, (MeNH₃)PbX₃

Perovskite solar cells, the so-called organic-inorganic hybrid solar cell, which were first reported in 2009 by Miyasaka et al. recently received much attention.¹⁾ The organic-inorganic perovskite crystal, (MeNH₃)PbI₃, can functionalize as a visible light sensitizer toward titanium dioxide. In the solar cell device with a hole transport material (eg. Spiro-OMeTAD), the energy conversion efficiency has been more than 15% so far, thus it is greater than those of organic photovoltaics (OPV) and dye-sensitized solar cells (DSSC).^2,3) The perovskite solar cell is able to output more than 1 V, because the perovskite compound shows strong absorptivity of light and then efficiently transports both electron and hole carriers without their recombination. A device of the perovskite solar cell can be fabricated by a solution process for manufacturing at low cost.

A modification of X in the (MeNH₃)PbX₃ can control the band gap and range of absorption wavelength. The perovskite compound with X = Br is useful for photo absorption in shorter wavelengths (<560 nm) and the compound with X = I is relatively useful for that in longer wavelengths up to 800 nm.¹⁾ Methylamine hydroiodide (1) or methylamine hydrobromide (2) is reacted with lead(II) halide to give the corresponding organic-inorganic perovskite compound, (MeNH₃)PbX₃ (X = Br or I).