Lecture 8 : Solar cell technologies, world records and some new concepts. Prof Ken Durose University of Liverpool

Transcription

1 Lecture 8 : Solar cell technologies, world records and some new concepts Prof Ken Durose University of Liverpool

2 Review papers on PV there are lots do read one or two! Materials Today 2007

3 NREL efficiency chart one of a kind cells Download the latest version for your work!

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5 Progress in PV Efficiency Tables the gold standard

6 World Record Cells (and sub-modules) Criteria for inclusion (cells): Independently measured by a recognised test center elsewhere Area > 1cm 2 (= total area!) for one sun devices Other rules for minimodules and concentrators Single junction types Silicon III-V Thin film chalcogenide Amorphous/microcrystalline Si Perovskite Dye sensitised Organic

7 World Record Cells List June 2018

8 World Record Cells a review of the single junction types Crystalline silicon single crystal and multi-crystalline III-V (GaAs) CIGS CdTe -Si/ nc-si (amorphous/nanocrystalline) Perovskite Dye sensitised (DSSC) Organic (OPV)

9 Sand Purification of silicon 98% pure Si HCl SiHCl 3 Distil Heat under H 2 Begin PV production Grow crystal Or cast ingot Pure Si ad.jpg

10 Silicon the world leader

11 Si large scale production

12 Silicon - crystalline

13 Silicon s best the Sanyo HIT cell Heterojunction with Intrinsic Thin layer Highest-Energy-Conversion-Efficiency-of-23-0-

14 Silicon - crystalline Pic from Miles 2007

15 Silicon multi-crystalline Advantages Cheaper than wafer silicon Uses silicon processing technology Disadvantages 5% less efficient than single crystal (Highest efficiencies need exotic processing (left)) Ref Shultz 2004

16 Silicon multi-crystalline Pic from Miles 2007

17 Ref 24 Kayes 2011 III-V

18 Ref Kayes 2011 III-V

19 Thin film - CIGS Image from NREL Strengths High efficiency ~ 20% Thin film construction Issues Complex material chalcogen loss In and Ga rare and expensive Business hard to sustain danger of it being undercut

20 Thin film - CIGS MC silicon CIGS CIGS

21 Thin film - CdTe Strengths Easy to produce Cheapest PV you can buy Main competitor to silicon Major improvements in recent years 16 20% Weaknesses Cd is toxic Te is quite scarce

22 Thin film - CdTe glass contact CdTe CdS or CdSe Transparent conductor These graphs - Wu about 16.5%

23 CZTSS = Cu 2 ZnSn(S x Se 1-x ) 4 50 Winkler Eg = 1.16 ev; Voc = 0.5 V - a 57% shortfall (very poor) E g V oc E F World annual production tonnes/year

24 CZTSS New category in 2016! Down from 12% in notable exceptions!

25 Thin film amorphous silicon Pic from Miles 2007 Advantages a-si is a direct gap semiconductor! Dundee 1970 s Problems Its not stable The efficiency is low No longer in serious production

26 Thin film microcrystalline silicon Advantage it s not wafers! Low cost thin film silicon could revolutionise solar power Disadvantage Silicon is an indirect gap material and does not absorb well Need to use tricks to get it to work

27 Thin film microcrystalline silicon Ref Sai uses honeycomb textured substrate

28 Hybrid Perovskite New category in 2016! FAPbI Advantages: 3 Possible cheap PV route Got efficient very quickly Disadvantages: Unstable, hysteretic, contains Pb

29 Progress in PV Tables (version 52) Statement on perovskite solar cells

30 Dye sensitised solar cell DSSC Strengths Does not require high purity semiconductors Potentially cheap to produce with simple equipment Weaknesses Liquid electrolyte causes instability Efficiency seems to be stuck at just over 10% More difficult to manufacture than expected

31 Dye

32 Organic Bulk heterojunction: P3HT e donor C60 derivative e acceptor Al electrode glass PEDOT:PSS Transparent conductor Image from L M Peter Royal Soc P3HT poly-3-hexyl-thiophene

33 Organic Advantages Has potential for low cost Disadvantages Unstable absorption is an antibonding transition Low efficiency Companies can t make it pay

34 Organic R Service Science 2011

35 Multi-junction solar cells brief review

36 Multi-junction III-V

37 Multi-junction III-V Concentrator Tracker 600 x concentration ~40% efficient Has accurate tracking system Needs direct sunlight Pics from Circadian Solar Ltd &

38 Multi-junction III-V Advantages Very high efficiency Can be used with tracking concentrator systems Disadvantages High cost

39 Multi-junction III-V Ref 32 Chiu 2014

40 Perovskite with wafer silicon Advantage combines an existing market winner with a new technology capable of increasing the overall performance

41 Multi-junction thin film silicon Advantage All-Si multi-junction using a-si (1.7 ev) Microcrystalline Si (1.1eV) Disadvantage Complex for the efficiency gained.

42 Notable Exceptions category Things that are worth reporting but didn t make it to the record tables

43 Notable Exceptions Version 52

44 Modules From Progress in PV efficiency tables version 51, 2017

45 Other concepts - things that didn t make it to the tables yet

46 Intermediate band cells Conduction band Intermediate band Valence band

47 Quantum dot cells Rsc/ Univ Texas ETH Zurich

48 Nanowire PV TCO CdS CdTe foil