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Home > The Amp Hour Electronics Podcast > #433 – An Interview with Sam Stranks


	Podcast:		The Amp Hour Electronics Podcast
	Episode:		#433 – An Interview with Sam Stranks
	Category:		Science & Medicine
	Duration:		01:10:59
	Publish Date:		2019-03-10 18:55:51
	Description:		Welcome Dr Sam Stranks, entrepreneur and professor at Cambridge University! Perovskites 0h 0m 49s The family is based on the crystal structure 0h 1m 15s Have been worked on for 2 to 3 decades 0h 1m 44s Only since 2009 have they been used as a solar cell 0h 2m 36s Sam’s background is physicist 0h 4m 46s Raised in Australia 0h 6m 23s Broad undergrad background 0h 7m 0s Bridged chemistry and physics in Master’s program 0h 7m 22s Worked on removing white wine proteins 0h 7m 32s The mechanism is similar to how alzheimers blobs together 0h 8m 50s 2007 0h 10m 24s He got a Rhodes scholarship which meant he ended up going to Cambridge University. 0h 10m 29s Research included carbon nanotubes 0h 11m 7s Wrapping polymes around then 0h 11m 21s Popularity has been dropping 0h 11m 47s Fullerenes, Graphene both won Nobel prize. 0h 12m 2s Producing nanotubes is difficult 0h 12m 21s Dave made a video about a bunkum Kickstarter doing Graphene heaters 0h 12m 34s Specifically separating out metallic and semiconductor types 0h 12m 47s Finished PhD 2012 0h 15m 5s Joined Henry Snaith‘s group doing dye sensitized solar cells 0h 15m 21s Reemergence of perovskites 0h 16m 21s The initial focus was on a dye sensitive cell made out of perovskite 0h 18m 25s Early efficiency was 3% 0h 18m 56s The research is done in a place that looks more like a chemistry lab than a semi lab 0h 22m 23s Solar simulator to replicate the sun 0h 23m 40s How are perovskites different from solar cells? 0h 25m 34s Silicon has an indirect bandgap 0h 26m 49s Multijunctions cells (the kind on satellites) have different absorbers (different colors) 0h 27m 52s Record silicon efficiency is 27% 0h 28m 21s Full panel is about 20% 0h 28m 39s Perovskite is at 23% 0h 29m 5s Triple junction is 39% 0h 29m 27s Videos from past guests Sam Zeloof and Jeri Ellsworth 0h 30m 53s Printed solar cells 0h 32m 4s ABX3 0h 34m 4s Thickness only needs to be half a micron 0h 34m 41s The name ‘perovskite solar cell’ is derived from the ABX3 crystal structure of the absorber materials, which is referred to as perovskite structure. The most commonly studied perovskite absorber is methylammonium lead trihalide (CH3NH3PbX3, where X is a halogen atom such as iodine, bromine or chlorine), with an optical bandgap between 1.5 and 2.3 eV depending on halide content. Formamidinum lead trihalide (H2NCHNH2PbX3) 0h 35m 56s Currently using Indium for the contact, but it’s hard to get, running out 0h 36m 13s Talking through the stack 0h 37m 12s Bottom electrode is Indium Tin oxide 0h 37m 37s Then a layer of perovskite 0h 37m 53s Top layer is organic 0h 38m 37s Illumnate through the glass, 0h 39m 33s InSnOx is transparent up to UV 0h 41m 14s Perovskite absorbs 200-800 0h 41m 28s Using lasers to test with pulses 0h 44m 57s Pulses for a 1 ps 0h 45m 7s Monitor how they recombine and lose energy 0h 45m 38s What causes a defect? 0h 46m 23s What actually makes electrons mobile in the ABX3 structure? 0h 49m 15s Structure is mostly from the B and the X (lead and iodide) 0h 49m 35s Covalently bonding vs ionic bonding 0h 52m 35s Other applications being targeted 0h 56m 47s Light emission (LEDs) 0h 56m 57s Also using for lasing materials (LASERs) 0h 59m 41s Want to make an electrically pumped laser 0h 59m 55s Have been some changes in the A site that stabilize ion migration 1h 1m 55s Sam is a founder of Swift Solar 1h 2m 29s The 6 founders had spent time together in Henry Snaith’s group 1h 2m 43s Focusing on making tandem cells 1h 3m 20s Making a solar sheet 1h 4m 13s More solar cells in a smaller area 1h 4m 59s Payback periods 1h 5m 25s Why hasn’t this started on the production side yet? 1h 6m 18s Solar is coming down to 20 cent per watt 1h 6m 43s Install costs are still $1 per watt 1h 6m 56s The lightweight aspects lowers the cost of installation 1h 7m 20s Sam did a TED talk 1h 8m 13s Integrated photovoltaics 1h 8m 25s Group web page 1h 9m 27s Want to learn more about bandgaps? Check out pveducation.org 1h 9m 33s Scientific American wrote an article about The Perovskite Boom last year 1h 9m 54s Sam’s lab is taking new students! Reach him via his web page or reach out to him on Twitter (@SamStranks) 1h 11m 59s Photo: Ryan Lash / TED
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