Improving　power　conversion　efficiency　(PCE)　in　photovoltaics　has　driven　innovative　approaches　in　solar　cell　design　and　technology.　Silicon　heterojunction　(SHJ)　solar　cells　exhibit　advantages　in　PCE　due　to　their　effective　passivating　contact　structures.　SHJ–interdigitated　back　contact　(SHJ–IBC)　solar　cells　have　the　potential　to　surpass　traditional　SHJ　cells,　attributed　to　their　advantage　in　short-circuit　current　(JSC).　Herein,　Silvaco　Atlas　technology　computer-aided　design　is　used　to　create　digital　twins　of　high-efficiency　SHJ　solar　cells　with　amorphous　silicon　and　nanocrystalline　silicon　hole　selective　contact　(HSC)　layers.　Using　parameters　from　digital　twins　of　SHJ　solar　cells,　the　practical　efficiency　limit　of　SHJ–IBC　solar　cells　is　assessed.　The　results　show　that　SHJ–IBC　cells　can　achieve　potential　efficiencies　of　27.01%　with　amorphous　HSC　and　27.38%　with　nanocrystalline　HSC.　Further　efficiency　augmentation　to　27.51%　can　be　achieved　by　narrowing　the　gap　from　80　to　20　μm.　This　study　not　only　advances　comprehension　of　SHJ–IBC　solar　cells　but　also　provides　insights　into　optimizing　geometrical　configurations　for　improved　performance.　The　utilization　of　digital　twins　provides　a　valuable　tool　for　predicting　and　evaluating　the　performance　of　SHJ–IBC　solar　cells,　contributing　substantively　to　the　ongoing　development　of　high-efficiency　photovoltaic　technology.　©　2024　Wiley-VCH　GmbH.