“…With the versatility of slot-die coating and the ability to coat using a range of viscosities, there have been a wide range of materials coated with this technique, including but not limited to active layer blends (i.e., P3HT:PCBM [ 90 , 165 ], PPDT2FBT:PCBM [ 67 , 88 ], PBDB-T:ITIC [ 113 ], and PM6:Y6 [ 170 , 175 ]), electron (i.e., ZnO NPs [ 161 , 162 , 170 ], SnO 2 [ 58 , 176 ], PEI [ 139 ], and AZO [ 85 , 153 ]) and hole transport layers (i.e., PEDOT:PSS [ 139 , 165 ]), and electrodes (i.e., AgNWs [ 176 , 177 ]). As for the number of layers coated via slot-die coating on a single device, a significant amount of papers have implemented this technique for two [ 155 , 162 , 178 ] or three layers [ 104 , 105 , 154 , 179 ], with a minor amount applying the technique for a single layer [ 42 , 65 , 87 ].…”