If you are in the science field and have a particular interest in Energy, then you are more than likely to have heard of perovskite solar cells. These devices which are set to change the way we power our homes, etc. have grown from strength to strength from 3.8% efficiency in 2009 to 22% in 2016. It is another light harvesting system which is able to generate electricity, but how does this happen? and what has this got to do with the heart?
In any solar cell (e.g. dye sensitised solar cells), the most important thing is that light comes into the system, electrons are photo-generated (generated by light) and they flow freely around a circuit = electricity! The stages by which an electron transitions from a bound state to freely moving around a circuit happens in different ways depending on the system. In perovskite solar cells one way is via a thin film solar cell, which is a layered system consisting of a p-type layer, an n-type layer and a perovskite structured material in the middle (see figures below).
Perovskite solar cell – image from Albero et. al., J. Mater. Chem. A, 2016,4, 4353-4364 (left). Perovskite structure – image from Eames et.al. Nature Communications, 2015,6, 7497 (right).
When light enters, each perovskite molecule will divide into an electron and a “positive hole”, which is essentially the molecule without the negative electron. This occurs because the light provides enough energy for the electron to eject from the atom. This division is known as “charge generation” because a negative electron is formed and so is a positive hole. These then undergo “charge separation”, where positive holes go toward the p-type layer and electrons toward the n-type ready to power the system by flowing around a circuit = electricity.
God’s Word is quite like ‘the light’, dividing us into our bare components like the electron and the hole. The Bible says, “For the Word of God is living and active. Sharper than any double-edged sword, it pierces even to dividing to soul and spirit, joints and marrow. It is able to judge the thoughts and intentions of the heart” (Hebrews 4:12). Not only do we want God to come into us like a ray of light in a perovskite solar cell or as a double edged sword, as described in the Bible, to divide us up into who who really are, but we also want Him to generate/ create in us, a clean heart. “Create in me a clean heart, O God, and renew a steadfast spirit within me” (Psalm 51:10). That way, once God has generated that heart that is pure, it is ready to to (em)power the world like these photo-generated electrons.
For a neat video on perovskite solar cells visit: https://www.youtube.com/watch?v=crAugJXG3QA