You could convert it to a cell array and use cellfun

B=mat2cell(reshape(A,[1, size(A,2).^2, size(A,3)]),[1],[size(A,2).^2], [ones(size(A,3),1)]);
[M,I]= cellfun(@max,B)
[R,C] = ind2sub(size(A),I);

M contains the maximum value and I the corresponding index.

Assuming that A is a 3x3x2 array.

A =[

    0.7952    0.4456    0.7547
    0.1869    0.6463    0.2760
    0.4898    0.7094    0.6797];

A(:,:,2) =[

    0.6551    0.4984    0.5853
    0.1626    0.9597    0.2238
    0.1190    0.3404    0.7513];

Convert each slice into a 1x9x2 cell array

B=mat2cell(reshape(A,[1, size(A,2).^2, size(A,3)]),[1],[size(A,2).^2], [ones(size(A,3),1)]);

B(:,:,1) = 

    [1x9 double]


B(:,:,2) = 

    [1x9 double]

Take the maximum of each slice. R is the row and C is the column for the respective maximum value in M.

[M,I]= cellfun(@max,B)
[R,C] = ind2sub(size(A),I)

R(:,:,1) =

     1

R(:,:,2) =

     2

C(:,:,1) =

     1

C(:,:,2) =

     2

You can use arrayfun as following:

c=arrayfun(@(i) X(:,:,i)*Esun(i),1:8,'UniformOutput',0);

Assuming that X is your image array. In the above, MATLAB return a 1x8 cell array, then you can use cat function to obtain the new array:

B = cat(3, c{:}); % cat all cell elements in 3-rd dim