SET ' s ▁absor ber ▁had ▁the ▁ 2 nd ▁lowest ▁efficiency ▁at ▁ 8 . 6 %. ▁However , ▁all ▁the ▁modules ▁that ▁beat ▁I SET ' s ▁module ▁were ▁co ev apor ated , ▁a ▁process ▁which ▁has ▁manufact uring ▁dis adv antages ▁and ▁higher ▁costs . ▁I SET ' s ▁sample ▁suffered ▁most ▁from ▁low ▁V OC ▁and ▁low ▁fill ▁factor , ▁indic ative ▁of ▁a ▁rough ▁surface ▁and / or ▁a ▁high ▁number ▁of ▁defect s ▁a iding ▁recom bin ation . ▁Rel ated ▁to ▁these ▁issues , ▁the ▁film ▁had ▁poor ▁transport ▁properties ▁including ▁a ▁low ▁Hall ▁mob ility ▁and ▁short ▁car rier ▁lifetime . ▁ ▁Elect ro de position ▁followed ▁by ▁s elen ization ▁▁ ▁P rec urs ors ▁can ▁be ▁depos ited ▁by ▁electro de position . ▁Two ▁method ologies ▁exist : ▁de position ▁of ▁element al ▁layer ed ▁structures ▁and ▁simultane ous ▁de position ▁of ▁all ▁elements ▁( including ▁Se ). ▁Both ▁methods ▁require ▁thermal ▁treatment ▁in ▁a ▁Se ▁atmosphere ▁to ▁make ▁device ▁quality ▁films . ▁Because ▁electro de position ▁requires ▁conduct ive ▁electro des , ▁metal ▁fo ils ▁are ▁a ▁logical ▁substr ate . ▁Elect ro de position ▁of ▁element al ▁layers ▁is ▁similar ▁to ▁the ▁s put ter ing ▁of ▁element al ▁layers . ▁▁ <0x09> ▁Sim ult aneous ▁de position ▁emp lo ys ▁a ▁working ▁electro de ▁( c ath ode ), ▁a ▁counter ▁electro de ▁( an ode ), ▁and ▁a ▁reference ▁electro de ▁as ▁in ▁Figure ▁ 4 . ▁A