We present an approach for silicon (100) surface passivation using the organic small molecule, 1–10 phenanthrenequinone. Lifetime measurements show that on passivated silicon surfaces, recombination velocities of less than 100 cm/s can be achieved. Such electrically inactive surfaces are used to demonstrate a wide-bandgap organic/silicon heterojunction which reduces the effective minority carrier surface recombination at the metal/silicon contact compared to a similar structure without the organic layer.